Chapter  4:  Cataract in Adults: Management of Functional Impairment: Clinical Practice Guideline Number 4

Definition of Cataract

One significant problem in reviewing existing data is the varying definitions of "cataract" that are used in the literature. Different definitions are appropriate and depend on the research or program question that is being addressed. For epidemiologic studies of risk factors, it is important to identify the earliest lens changes that represent onset of disease. Thus, one definition of cataract is the presence of lens opacities. These lens opacities are objective changes and, as such, can be evaluated and recorded, and they may or may not have associated visual impairment or functional consequences (Adamsons, Munoz, Enger et al., 1991; Chylack, Leske, Sperduto et al., 1988; Leske, Chylack, Sperduto et al., 1988; West, Rosenthal, Newland et al., 1988). Thus, this definition may not be useful for addressing the visual or functional consequences of cataract.

A second definition frequently used is a lens opacity that causes, or is accompanied by, loss of visual acuity (Adamsons, Munoz, Enger et al., 1991; Hiller, Sperduto, and Ederer, 1983; Kahn, Leibowitz, Ganley et al., 1977). This definition has been used in prevalence surveys to identify lens opacities that are severe enough to interfere with vision. A problem with this definition is that other causes of visual acuity loss besides (or in addition to) the lens opacity must be excluded. Moreover, advanced lens changes, particularly cortical changes, can be present with no accompanying loss of acuity. Nevertheless, if data are needed on visually significant cataract, some component of loss of visual function must be included in the definition. The level of visual acuity loss may be modest (in Framingham, best visual acuity of 20/30 or worse was selected as a cutoff [Kahn, Leibowitz, Ganley et al., 1977]). However, current discussions in the ophthalmic literature report that visual acuity may not be the only appropriate vision function parameter to measure in cataract, with loss of contrast sensitivity and glare representing visual consequences more sensitive to cataractous change (Drummond, 1990).

A third dimension of cataract relates to the functional consequences of lens opacification for everyday activities. Clinicians are well aware of patients with 20/40 cataracts who report no functional disability associated with their ocular status, although other patients with seemingly good vision have curtailed driving activities. The focus of this document is the care of the patient with functional disability due to cataract.

Each of these different approaches to the definition of lens opacity or cataract has relevance in the context of the research or program focus in which it is used. However, when attempting to describe the "natural history" of cataracts, one must be precise in the definition of cataract and be aware that the implication of using any one definition will alter the epidemiologic picture. Moreover, there will also be large differences in the epidemiology of the different cataract types.

Prevalence Data

Population-based data on prevalence of cataract in the United States aare few. Three sources that will be reviewed are the Framingham Eye Study, the National health and Nutrition Examination Survey, and the Watermen Study.

Table 1-1. Percent of Persons with Lens Opacity and (more...)

Table 1-1. Percent of Persons with Lens Opacity and Cataract Based on Different Surveys, by Age

Source	< 35	35-44	45-54	55-64[1]	65-74	75-84[1]	85+
Framingham[1] (Source: Kahn, Leibowitz, Ganley et al., 1977)
Lens opacities	-	-	-	41.7	73.2	91.1	-
Cataract	-	-	-	4.5	18.0	45.9	-
NHANES[2] (Source: Leske and Sperduto, 1983)
Lens opacities	-	-	12.2	27.6	57.6	-	-
Cataract	-	-	2.6	10.0	28.5	-	-
Watermen[3] (Source: Taylor, West, Rosenthal et al., 1988)
Lens opacities	1.8	2.7	5.7	37.0	72.1	94.2	100.0
Cataract	-	-	-	5	25	59	-

[1] Both sexes combined. Population ranged from age 52 to 85, so those age 85 are included in last grouping, and those age 52-54 are among the 55 -64 group; white residents only.

[2] Both sexes and all races combined.

[3] Men only. Population ranged from age 30 to 94. Only those age 50-85 were studied for cataracts, defined as lens opacities accompanied by visual acuity of 20/30 or worse.

In summary, although lens opacities are often found in those under age 45, there are no prevalence data on functional cataract to compare with the data on lens opacities or early cataract.

Table 1-2. Percent of Persons with Cataract Types Based (more...)

Table 1-2. Percent of Persons with Cataract Types Based on Different Prevalence Surveys, by Age

Source	Nuclear	Cortical	PSC	Mixed
Framingham[1] (Source: Sperduto and Hiller, 1984)
< 35	-	-	-	-
35-44	-	-	-	-
45-54	-	-	-	-
55-64	5.7	4.6	2.2	5.4
65-74	18.9	9.9	2.4	17.9
75-84	30.0	5.8	1.3	36.5
85+	-	-	-	-
Watermen[1](Source: Adamsons, Muñoz, Enger et al., 1991
30-39	0	< 1	< 1	< 1
40-49	4.1	0	0	0
50-59	11.5	3.6	< 1	2.4
60-69	33.0	7.4	0	15.3
70-79	45.7	7.6	0	33.3
80+	38.9	5.6	0	55.6
Surgical Series[2](Source: Adamsons, Muñoz, Enger et al., 1991
< 50	5.6	0	77.8	16.7
50-59	16.1	3.0	45.2	35.5
60-69	12.2	12.2	31.7	43.9
70-79	35.1	7.0	5.3	52.6
80+	19.4	8.3	8.3	63.9

[1] Data are for lens opacities.

[2] Data are based on a series of 183 cataract surgery patients.

The contrast with the types of cataract that actually present for surgery is interesting, in that among the younger ages, PSC was the predominant cataract type (Adamsons, Munoz, Enger et al., 1991). Most of the mixed cases, at least in this series, also included PSC, suggesting that PSC is a significant cause of functional cataract, if not a prevalent one.

Incidence and Progression

Understanding the natural history of lens opacities and cataract will depend on knowledge of the incidence of lens opacities and progression of opacities to cataracts in the population. Such data are currently unavailable, although some longitudinal studies are now under way. Clearly, there is a need to acquire data on age-specific incidence of cataract, especially functionally significant cataract, for purposes of planning eye care delivery for the older population in the United States and other countries. The sparse data that are available and summarized here are based on statistical projections of population studies, prospective evaluations of ill-defined case series that used untested methodologies, and abstracts from meetings reporting current approaches.

Table 1-3. Age-Specific 5-Year Incidence of Lens Opacities (more...)

Table 1-3. Age-Specific 5-Year Incidence of Lens Opacities and Cataracts: Framingham Eye Study

Age	Lens Opacities (Percent)	Cataracts (Percent)
55	10	1
60	16	2
65	23	5
70	31	9
75	37	15

Source: Podgor, Leske, and Ederer, 1983.

Table 1-4. Age-Specific Incidence of Cortical or Nuclear (more...)

Table 1-4. Age-Specific Incidence of Cortical or Nuclear Lens Opacities: Watermen Eye Study [1]

Age	Cortical (Percent)	Nuclear (Percent)
30-39	1	< 1
40-49	3	2
50-59	8	12
60-69	17	32
70-79	32	51
80+	32	55

[1] The opacities are not mutually exclusive.

Source: S. West, personal communication.

Conclusions

There is a significant need for a sensitive and reliable system to detect cataract change for longitudinal studies (Munoz, West, Wang et al., 1991). Several methods have been proposed, and all are prone to measurement error, which in some cases can result in equal amounts of "improvement" and progression. Data from case series suggest that progression rates of opacities may be higher than the incidence of new opacities (Chylack, Leske, Khu et al., 1989; Magno, Datiles, Sperduto et al., 1991). This observation needs to be studied in population series to confirm the validity.

More information on incidence and progression will be generated from currently funded research projects on risk factors for lens opacities. However, few of the current studies are designed to evaluate the incidence of cataracts that cause functional disability or to determine the progression of cataracts from having no functional consequences to those causing functional loss. This research is clearly necessary to evaluate the likely onset of functional loss from lens opacities and the probable need for cataract surgery in the future.

Such studies are difficult to undertake for at least two reasons. First, instruments to measure the functional impact of cataracts are in the developmental stage. Many instruments on functional status do not include measures likely to be affected by decreases in vision or glare. Special instruments designed to assess specific functional loss attributable to vision have not been completely validated. Additionally, comorbid conditions among those with cataract need to be assessed, as a decrease in vision may be exacerbated by the presence of other diseases to produce functional loss; conversely, any benefit from surgery may be mitigated by the presence of other conditions (Elam, Graney, Applegate et al., 1988). Despite these difficulties, there is growing recognition by policymakers that functional outcome and quality-of-life issues are important determinants of health care policy priorities (Drummond, 1990).

Ultraviolet-B Radiation

A number of ecologic studies have shown a higher prevalence of cataracts or lens opacities in populations living in areas with high ultraviolet-B (UV-B) radiation (Brilliant, Grasset, Pokhrel et al., 1983; Hiller, Sperduto, and Ederer, 1983; Hollows and Moran, 1981; Taylor, 1980). The consistency of the association despite different populations and study methodologies strengthens the likelihood that UV-B is a causal factor. Recent studies using measures of personal exposure to UV-B have shown that cortical opacities and PSC opacities are related to cumulative lifetime exposure to UV-B (Bochow, West, Azar et al., 1989; Taylor, West, Rosenthal et al., 1988). These studies have also shown the important effect of sunglasses and hat use in reducing ocular exposure to UV-B. However, because the amount of risk attributable to UV exposure is unknown, it is not possible to estimate the effect of such protection on the likelihood of developing a cataract that will require cataract surgery.

Diabetes

Diabetics appear to be at higher risk for cataract compared with nondiabetics (Ederer, Hiller, and Taylor, 1981). The excess mortality associated with cataract patients is confined to those with diabetes (Podgor, Cassel, and Kannel, 1985), and diabetics with cataracts appear to be at greater risk of death than those without cataracts (Cohen, Neil, Sparrow et al., 1990). The mechanism of action for "sugar cataracts" was described in several reviews (Kinoshita, 1990; Kinoshita, Fukushi, Kador et al., 1979). PSC, cortical, and mixed opacities were the types most commonly associated with diabetes in case-control studies (Bochow, West, Azar et al., 1989; Leske, Chylack, and Wu, 1991).

Drugs

Several drugs have been proposed as potentially cataractogenic, although detailed studies are few. The association between corticosteroid use and risk of PSC cataract is well known (Black, Oglesby, von Sallman et al., 1960; Bochow, West, Azar et al., 1989; Italian-American Cataract Study Group, 1991; Leske, Chylack, and Wu, 1991), although controversy remains over the role of individual susceptibility and dose or duration of steroid therapy. The possible protective effect of aspirin was not confirmed by data from several studies (Peto, Gray, Collins et al., 1988; Seddon, Christen, Manson et al., 1991; Seigel, Sperduto, and Ferris, 1982; West, Munoz, Newland et al., 1987). It is unlikely that aspirin in prophylactic or sporadic doses is protective against cataract formation.

Diuretics have been implicated in cataractogenesis (Clayton, Cuthbert, Seth et al., 1984; Klein, Klein, and Moss, 1985; Mele, Alston, Moorman et al., 1990). However, it is difficult to disentangle the effect of the diseases for which these drugs are prescribed from the effect of the drugs themselves. In one study with longitudinal data on thiazide use, the risk of cortical opacities was highest in individuals using thiazides for 4 or more years, but they also had hypertension of long duration (Mele, Alston, Moorman et al., 1990).

Major tranquilizers, particularly phenothiazines such as chlorpromazine, were associated with increased risk of cataract (Clayton, Cuthbert, Seth et al., 1984; Collman, Shore, Shy et al., 1988). Another study with longitudinal data on phenothiazine use was equivocal, with no evidence of a dose-response relationship with cataract extraction (Isaac, Walker, Jick et al., 1991). Patients with decreased vision, including vision loss from cataract, are known to be depressed (Elam, Graney, Applegate et al., 1988). Association of the use of these drugs in the recent past with cataracts (particularly with cataract extraction) may be more reflective of the depressive consequence of vision loss.

Smoking

Risk of nuclear opacities from smoking was first reported in 1989 (est, Munoz, Emmett et al., 1989) and was confirmed in other studies (Christen, Manson, Seddon et al., 1992; Flaye, Sullivan, Cullinan et al., 1989; Hankinson, Willett, Colditz et al., 1992; Leske, Chylack, and Wu, 1991). In addition, there may well be an increased risk of developing PSC cataract (Christen, Manson, Seddon et al., 1992; Hankinson, Willett, Colditz et al., 1992). Exsmokers appeared to have a lower risk than current smokers, regardless of amount smoked.

Diarrhea

Another factor of potential importance is the possible effect of severe diarrheal episodes on cataractogenesis. This may be of greater relevance in countries where diarrhea is endemic and more severe than in the United States. The data, however, are conflicting: one study found a 21-fold increased risk of cataract associated with two or more episodes of severe diarrhea (Minassian, Mehra, and Jones, 1984); several other studies have found no association (Bhatnagar, West, Vitale et al., 1991; Mohan, Sperduto, Angra et al., 1989).

Alcohol

Several studies have now reported an association between heavy drinking and cataracts (Clayton, Cuthbert, Duffy et al., 1982; Harding and van Heyningen, 1989; Munoz, West, Tajchman et al., forthcoming; van Heyningen and Harding, 1988). One study found a fourfold increased risk of PSC cataract in those who were consuming one drink per day on average. As alcohol consumption is fairly ubiquitous worldwide, this hypothesis deserves further investigation in other settings.

Antioxidant Vitamins

Nutritional status and cataracts present a complex and confusing picture. The data from human studies are sparse and incomplete. One problem is the high correlation among dietary intakes of various nutrients. For example, early work in India suggested diets low in protein may be a risk factor for cataract; however, these diets may be low in a number of micronutrients (such as riboflavin) as well (Chatterjee, Milton, and Thyle, 1982).

Current studies are suggestive of an increased risk of cataract associated with low antioxidant status (Jacques, Chylack, McGandy et al., 1988; Jacques, Hartz, Chylack et al., 1988; Leske, Chylack, and Wu, 1991; Vitale, West, Hallfrisch et al., 1991). However, the type of cataract associated with low antioxidant status varies from study to study, and the constituents of the "antioxidant indices" vary, making the results of this body of work inconclusive. It is premature to recommend vitamin ingestion as a control strategy until further research is more definitive (West, 1991).

Conclusions

The last 5 years have produced a wealth of data on risk factors for cataracts. Cataract is clearly a multifactorial disease, and different factors are associated with different types of opacities. The findings are encouraging for those risk factors at which simple, preventive strategies might be targeted, such as decreasing sun exposure, increasing antioxidant vitamin use, or smoking cessation. For example, use of UV-absorbing glasses and a hat would reduce exposure to UV-B light. However, because the amount of risk attributable to UV exposure is unknown, it is not possible to estimate the effect of such protection on the likelihood of developing a cataract that will require surgery.

Further research is needed to develop and assess the impact of strategies designed to reduce or retard the development of cataract. The potential saving in human suffering and cost that could result from preventing or retarding cataract development and progression, including the possibility of precluding development of functionally significant cataract in a large proportion of elderly, is enormous. At this time, management guidelines on reducing the risk of cataract cannot be provided.

Cost of Care

The panel found no published data regarding the frequency with which various preoperative, intraoperative, and postoperative services are provided in connection with extraction of a cataract or regarding the cost of those services. The panel, therefore, asked the AHCPR-funded Cataract Patient Outcomes Research Team (PORT) to assess both the content and cost of an episode of cataract surgery through analyses of a sample of 1986-87 Medicare claims data (for beneficiaries 65 years of age or older). In addition, a sample of 1987-89 private insurance claims data (for individuals under age 65) was purchased from MEDSTAT Systems, Inc. (Ann Arbor, MI).3

[3] The data presented in this section are derived from Earl P. Steinberg, MD, MPP, et al., "The Content and Cost of an Episode of Cataract Surgery," manuscript submitted for publication.

In summary, this analysis suggests that Medicare expended approximately $3.4 billion in connection with cataract surgery in 1991. Of this, only $64 million (2 percent) is estimated to have been spent on miscellaneous ophthalmic diagnostic tests and perioperative medical services. The primary determinants of Medicare's cost of cataract surgery are thus the overall frequency with which cataract surgery and YAG laser capsulotomy are performed and the amounts paid for these core components of an episode of cataract surgery.

Development of Methods and Questions

To prepare for the development of the guidelines by the panel, a meeting of the Ad Hoc Literature Review Group was held in Washington on July 19, 1990. The purpose was to develop a list of literature search questions to be answered by the literature review. It was decided that the questions would be oriented toward aspects of the care of patients with functional impairment due to cataract as they relate to outcome. The questions were divided into 13 categories. At the same time, criteria for including and excluding articles in the literature review were also developed.

A two-pronged approach to the literature search was devised in which both content and methodologic quality would be evaluated. The Ad Hoc Literature Review Group unanimously agreed that content relevance was of prime importance in establishing the literature to be reviewed for this panel. To achieve this goal, teams of content experts would first review and select the publications based on content relevance. Methodologists would then review the selected publications and come to consensus regarding quality and conclusions, using criteria established to ensure appropriate rigor. A content review team leader and a methodologist for each category would be appointed.

This overall approach, the literature search questions, and the inclusion/exclusion criteria developed by the Ad Hoc Literature Review Group were approved by the guideline panel at its first meeting in August 1990. The content review team leaders were then selected by Denis O'Day, MD, Panel Chair, on the basis of known expertise in the area under consideration. Subsequently, team leaders in collaboration with Dr. O'Day appointed literature review team members. A similar approach was used to select methodologists for the project.

The members of the Ad Hoc Literature Review Group decided to use the data bases of the National Library of Medicine as the foundation. Because of the limitations of timeliness and breadth inherent in such data bases, less formal methods of literature search were also used. These included reviewing research and professional meeting abstracts, writing to journal editors of impending and relevant articles, reviewing government studies, and surveying interest groups for relevant information.

As a result of the informal literature search process, two articles considered worthy of review were brought to the attention of the Ad Hoc Literature Review Group during the open forum. These articles dealt with cataract practice patterns and were sponsored, cited, and widely distributed by special interest groups advocating certain types of practice patterns. These articles were not published in a peer-review journal and were not annotated by the National Library of Medicine.

In light of the unique circumstances surrounding these publications and for the benefit of the panel, it was decided to review these separately. These full reviews are included in Appendix A in the Guideline Report. They are the reviews by William Stason, MD, and Steven Woolf, MD, MPH, of the Society of Geriatric Ophthalmology Special Report on Cataract Care and the review by Dr. Woolfof the Battelle Study, "Outcomes of Cataract Surgery With Co-Managed Postoperative Care" (Revicki, Brown, and Adler, 1990).

Selection of Potentially Relevant Articles

Printouts of the citations were sent to expert literature reviewers (abstract reviewers) to review and from which to select articles that appeared to be potentially relevant. In this first stage, the purpose of the selection process was to be "sensitive" as opposed to "specific." That is, the goal was to avoid overlooking any potentially relevant articles rather than to identify only articles that were definitely relevant to the question at hand.

Complete copies of the selected articles were retrieved from periodicals and reviewed by team leaders to determine whether articles satisfied the eligibility criteria. The same articles were also reviewed by methodologic evaluators for each team. The methodologist and team leader then communicated with one another to agree on a common set of articles deemed relevant for evaluation.

Development of Literature Evaluation Forms

The process of developing literature evaluation forms was concurrent with the process of identifying relevant articles. Two forms (a methodologic form and a content form) were used in evaluating an article. The methodologic form was developed by the methodologist for the team, and it addressed the following issues:

• Type of study design employed.

• Description of the patient population.

• Inclusion/exclusion criteria.

• Bias in patient selection.

• Sample size.

• Use of a comparison group.

• Potential bias in selection of patients or controls.

• Standardization of exposure or intervention.

• Standardization of definition and measurement of outcome.

• Use of masking of randomization.

• Duration of followup specified.

• Handling of attrition.

• Consideration of nonindependence of eyes for a single patient.

• Issues related to external validity of the study.

The content form typically was designed to address the specific search questions decided on by the Ad Hoc Literature Review Group in July 1990 and approved by guideline panel members in August 1990. These forms were generally developed by team leaders, with assistance from other Ad Hoc Literature Review Group members as needed.

Assessment of Content and Methodology

Once the final set of articles was selected for abstraction by content and methodology reviewers, copies of selected articles were mailed to members of each team for review and evaluation.

All articles mailed to the content reviewers were masked, so that the authors, their institutions, and the journal and year of publication were not visible. Articles were assigned to methods and content teams, with a common set of articles assigned to at least two members of those teams to allow assessment of interrater reliability.

Completed forms for the content reviews were returned to the team leader for summarization and analysis, and completed methods forms were returned to the methodologist for the same.

Interrater reliability for both the content and methods review was assessed by comparing duplicate abstractions by separate readers for the same article. For sections where only a few articles were evaluated, all articles were read and abstracted in duplicate and compared for reliability. When large numbers of articles were assessed, a sample of all articles was read and abstracted in duplicate and compared. Specific methods are described in the relevant chapters.

For the most part, no formal statistical analyses were done; rather the evidence was summarized in tabular form. The major reason for this was that study designs tended to vary substantially in clinically and methodologically significant ways. For example, patient eligibility criteria, outcome measures and definitions, and duration of followup varied substantially, precluding meaningful "pooling" of results.

Writeup of Literature Reviews

The panel was provided with drafts of the literature review results as they were completed. In some instances, the panel requested additional information that the members thought should be sought from the available literature. For example, in the case of potential vision, after the literature was initially reviewed and summarized in draft form, the panel requested a second review of the literature in order to identify articles containing data relevant to the effect of macular disease on the sensitivity and specificity of potential vision testing.

The reports for each of the sections of the Guideline Report were constructed in the same way. The Results section listed the questions initially identified by the Ad Hoc Literature Review Group and described the literature relevant to each question that met the inclusion criteria. The results of the literature review were also summarized in evidence tables.

In the chapters, text labeled "Discussion" centered on, first, the methodology of the studies included in the review and, second, their results. Sections labeled "Conclusions" were based primarily on the literature review. Only rarely did the panel present conclusions that were not based on the literature. When they did, they were careful to note where conclusions were based on the literature and where they expressed consensus opinion.

Consensus Process

In several cases, notably preoperative medical evaluation, there was very little available literature specifically appropriate to cataract surgery. In this case, guidelines that are not specific to cataract surgery were described, referencing the general medical literature where possible. Another example of a situation with little or no relevant literature was the chapter on Referral Pathways. When the panel needed to reach a consensus on an issue because of lack of data in the published literature, the mechanism was as follows: the person responsible for the chapter for which little or no data were available would write the chapter and conclusions based either on related literature, prior guidelines, or opinion. As with all chapters of the Guideline Report, the draft was distributed by mail to panel members for feedback. Using input from panel members, the responsible person would revise the draft several times prior to the next scheduled panel meeting. At the panel meeting, there would be considerable discussion regarding all conclusions, but in particular about conclusions for which a consensus had to be reached because there were no available data. At each panel meeting, drafts would be rereviewed and discussed again at length. The consensus process always involved panel members, and they were the only ones allowed to vote. No final decisions were made on chapters and their conclusions other than at panel meetings.

Methods

The purpose of the literature review was to identify and review those articles that contained information on the referral pathways for patients with functional impairment due to cataract. The referral sources to consider included self, internist, family practitioner, other ophthalmologist, other physician, other optometrist, nurse, social agency, social worker, health fairs, and nursing home screenings. (For a full description of the literature review and its results, see Appendix B in the Guideline Report.)

Results

The results of the literature review are given here and summarized in Evidence Tables B-1 to B-3 in Appendix B of the Guideline Report.

Conclusions From the Literature Review

No definite conclusions can be reached as a result of this review. Two papers, however, suggest that referral rates could be influenced by the referral source. General practitioners in Great Britain tended not to refer patients until surgery was imminent. Optometrists surveyed in Oklahoma tended not to routinely refer patients with symptomatic cataracts.

Methods

The purpose of the literature review was to determine whether there is evidence in the published literature to support or refute an association between the outcome of cataract surgery and the overall setting of care. (See Appendix C in the Guideline Report for a full discussion of the literature review process.)

Results

Each of 18 articles was evaluated with reference to the search questions. The results of the literature review are given here and summarized in Evidence Table C-1 in Appendix C of the Guideline Report.

Discussion

In the classification of these papers, only three broad categories were identified. One set focused on the clinical outcomes and complications associated with the provision of cataract surgical care by ophthalmologic resident physicians in training, often in comparison with faculty surgeons. There were seven studies in this category. The second category included five studies that focused on the measurement of the impact of the ambulatory provision of cataract surgical care in relation to inpatient surgery. The remainder dealt with various aspects of the organization and provision of ophthalmologic care (such as cost, quality, patient satisfaction, and the provision of care by optometrists and nurses to cataract patients) on the outcomes and complications of cataract surgery.

There is great variability among the studies reviewed. There appears to be a lack of consensus as to the most salient clinical or policy questions. Within those small clusters of projects that seem to study the same general issue, there is great variability in how the problem is formulated and in the way the principal variables are measured and results interpreted.

The lack of a "gold standard" for the measurement of the most important clinical outcomes seems to hamper these studies as a whole.

Few of the studies accounted for baseline differences among subjects (case mix) that might influence the clinical outcomes of greatest interest.

Summary

The set of papers reviewed here are, in general, methodologically weak and rely on nonexperimental methods with unspecified and unstandardized measures of either the independent or dependent variables of greatest importance. Most of the design inadequacies of these studies are correctable within feasible bounds of cost and convenience for those who would seek to answer these questions through further research. Moreover, the answers to these questions will make available information of considerable value to emerging public policy in the field of health and medical care.

Conclusions From the Literature Review

It is not possible to draw firm conclusions from the available scientific literature on these subjects regarding the influence of the type of provider, type of setting, or other features of the setting within which cataract surgical care is provided and the most common clinical outcomes (e.g., visual acuity and surgical complications). There seem to be strong suggestions in the existing literature that surgery performed (under supervision) for cataracts can be satisfactorily provided by residents with 2 or 3 years of postgraduate training with little difference in the critical indicators of clinical outcomes.

Site of Surgery

In the absence of data in the published literature, the panel reached the following conclusions by consensus.

Surgery should be performed where the patient can receive quality care in a safe environment, close to home if at all possible or close to the best social support system of family and friends. An outpatient setting can be in a hospital or in an independent surgery center. The selection of the site is the responsibility of the ophthalmologist who performs the surgery because the ophthalmologist is ultimately responsible for the care of the patient and is best qualified to judge the adequacy and safety of an operative setting.

The selection of the site of surgery should not be influenced by any financial relations between the operating ophthalmologist and the surgical facility or with the owners of the operating room. The selection of the site of surgery should not be influenced by the source of the patient referral.

The proximity of the setting for preoperative and postoperative care to the surgical site is important. In most cases, it is preferable that the perioperative care and surgery be performed in the same community. Proximity to the surgeon facilitates good postoperative care and is especially important when complications arise.

Sometimes a patient may choose to have surgery at a site far from home so that the postoperative course is with family or friends who can provide social, psychological, and practical support through the early postoperative period.

When the patient with cataract seeks surgery by an ophthalmologist located far from home, the provision of postoperative care by the ophthalmologist who performs the surgery becomes impractical; in that instance, the ophthalmologist should educate the patient about the importance of the continuum of the care process involved in cataract surgery. This includes the preoperative phase, the surgical procedure, and the period of postoperative care. If the patient still desires to have the surgery far from home, the ophthalmologist who is to perform the surgery should make formal and explicit arrangements before surgery for the provision of appropriate postoperative care that includes the capacity for dealing with complications and emergencies in a timely manner. The arrangements should include advice regarding temporary accommodations in the area where surgery is to be performed.

If anyone other than the operating ophthalmologist is to provide all or most of the postoperative care, then the operating ophthalmologist has an obligation to inform the patient before surgery of the arrangements and of the relative qualifications of the postoperative caregiver. The ophthalmologist assuming responsibility for the patient's postoperative care should be fully conversant with the surgical procedure and any unusual events or complications that occurred at the time of surgery and be fully capable of providing appropriate surgical intervention if required.

Providers of Care

The literature review failed to reveal useful information on important issues regarding providers of care. The panel reached the following conclusions by consensus.

From the patient's perspective, the operating ophthalmologist has a unique insight into and understanding of the patient's postoperative conditions, since he or she performed the surgery. Individual differences in cataract and individual differences in patient responses to surgery may lead to variations in the immediate postoperative outcome even in an uncomplicated operation.

The panel unanimously agreed that since the ophthalmologist who performs the surgery does so after discussing his or her assessment of the risks and benefits with the patient and after obtaining informed consent, and since that ophthalmologist has the most intimate knowledge of what took place at the time of surgery, he or she has the responsibility and ethical obligation to the patient for care during the postoperative period. The responsibility and obligation arise on the basis of the covenant that exists between the surgeon and the patient (see Ethics: The Relationship Between Caregiver and Patient, in the Overview).

From the patient's perspective, the period of postoperative care spans the interval from the conclusion of surgery until the goal of surgery is achieved by the attainment of stable improved vision. In the absence of complications, this usually occurs by 3 months after the surgery and coincides with the prescription of a final refractive correction. It also marks the point at which wound healing has sufficiently advanced so that the integrity of the eyeball has been reestablished and most short-term intraoperative and postoperative complications have been diagnosed and treated.

If ophthalmic medical and surgical postoperative complications develop, it is the obligation of the ophthalmologist who performed the surgery to provide treatment or, with the consent of the patient, to refer him or her to another ophthalmologist, depending on the nature of the problem. This treatment may need to extend beyond the postoperative period.

The surgeon must examine the patient the day after surgery, initiate appropriate postoperative treatment, monitor the patient's recovery from the surgery, diagnose and treat postoperative complications, or refer the patient to an ophthalmologist better able to deal with those complications (e.g., corneal decompensation, endophthalmitis, retinal detachment, and unexplained visual loss) and perform surgical revision when appropriate (e.g., cut sutures for treatment of postoperative astigmatism). To fulfill these responsibilities, the surgeon must examine the patient periodically until he or she is confident that the patient has fully recovered from surgery, a process that usually takes 6-12 weeks.

The surgeon cannot abrogate his or her responsibility for the patient's postoperative care; however, certain components of that care can be delegated to one or more members of a team of appropriately trained professionals.

At the present time, most ophthalmologists in the United States provide all of the postoperative care in their offices. Other ways of providing postoperative care utilize optometrists, visiting registered nurses, social workers, and other health care professionals. Some optometrists provide postoperative cataract care with varying amounts of involvement. Some optometrists assume the care of the patient from the ophthalmologists soon after surgery and refer detected medical and surgical complications back to the ophthalmologist for management. Some optometrists manage postoperative complaints independently, and others become involved in the care only after the eye has healed and is ready for refraction. In certain areas of the country, the patient receives part of the postoperative care at home from ophthalmic registered nurses.

These different patterns of postoperative care and the respective roles of the operating ophthalmologist, optometrist, visiting nurse, and other health care professionals are varied, vaguely defined, and lack standardization. The panel agreed that even with these new "team" approaches, the ophthalmologist who performed the surgery remains responsible for the surgical outcomes. Therefore, in addition to the responsibilities outlined above, the ophthalmologist must do the following:

• Be aware of the patient's needs, particularly as they relate to the eye, visual function, surgery-related complications, and the coexistence of systemic diseases.

• Be aware of the type and degree of competencies required to meet the patient's needs.

• Delegate or refer care to other providers if it is deemed appropriate and in the patient's best interest.

• Educate and advise the patient about the roles and competencies of specific individuals participating in the postoperative care.

• Be aware of and acknowledge cost considerations.

There should be a shared sense of responsibility among all those participating in a patient's postoperative care and visual rehabilitation. Part of this responsibility is to maintain sufficient communication so that care is coordinated and quality of care is monitored and maintained.

The literature search did not identify any study that addressed the effect of the services provided by ancillary medical personnel (e.g., ophthalmic technicians or technologists) on the outcome of cataract surgery. This is largely because most of these providers work within the operating ophthalmologist's office under his or her direct supervision and their contributions to patient care have not been analyzed separately or as part of a team approach.

The lack of studies on the availability of emergency care is probably because there is generally no problem of availability when ophthalmologists follow their own patients. Professional ophthalmic standards require the ophthalmologist who performs the surgery to be responsible for providing emergency care or to make arrangements for another ophthalmologist to do so.

The current practice of ophthalmology residents in training providing care, including cataract surgery under appropriate supervision, is satisfactory.

Test Description

Contrast sensitivity is a measure of the degree of contrast required to detect a test object. Snellen visual acuity measures the eye's ability to perceive high-contrast letters but does not adequately assess its ability to see low-contrast patterns. Contrast sensitivity testing attempts to determine the eye's ability to detect subtle variations of shading by presenting letters, figures, or sine wave gratings that are varied in contrast, luminance, and spatial frequency. Contrast sensitivity is determined by the lowest detectable contrast in which a subject is able to identify targets.

Numerous devices and methods have been developed to test contrast sensitivity. The simplest and least expensive methods employ reading cards or eye charts similar to those used in Snellen testing. More elaborate (and more expensive) methods involve the use of electronic devices (such as oscilloscopes) to generate sine wave gratings.

Literature Review Results

The results of the literature review are given here and summarized in Attachment 2 at the end of this document.

One hundred and nineteen papers on contrast sensitivity testing were reviewed by the contrast sensitivity content literature review teams. Ninety-eight of these were excluded because they did not meet the inclusion/ exclusion criteria set forth by the guideline panel. A total of 21 papers were reviewed for content and methodologic quality. Of these, only 10 provided data relating to the questions specified by the panel.

For the 21 articles reviewed for content, there was, in general, excellent agreement among content reviewers for items on the content evaluation form. In a few cases where there was disagreement, one of the reviewers changed his or her mind on reevaluating the study in question, or a third content reviewer was asked to review the article and cast the deciding vote. There was very poor agreement among content reviewers about the type of study (e.g., clinical trials), and these questions were therefore referred to the methodology reviewers with no attempt made to achieve consensus among content reviewers.

The results of the methodologic review of the 10 articles relevant to the questions posed by the panel are summarized in Attachment 2.

Very few of the 10 relevant articles met any of the methodologic criteria pertinent to studies that assess a preoperative test. Only two studies set out to assess contrast sensitivity testing as a test to document patients' complaints of visual impairment that may be useful in a preoperative evaluation (Elliott, Hurst, and Weatherill, 1990; Koch, 1989). Eight studies described contrast sensitivity testing in patients with different ocular pathologies or different types and severity of cataracts (Elliott, Gilchrist, and Whitaker, 1989; Hess and Woo, 1978; Howes, Caelli, and Mitchell, 1982; Lempert, Hopcroft, and Lempert, 1987; Maudgal, Stout, and vanBalen, 1988; Morris, Klett, Gieser et al., 1991; Singh, Cooper, Alder et al., 1981; Skalka, 1981a). These studies either did not use a gold standard for comparison of contrast sensitivity results or used one that was inappropriate for answering the questions posed in this literature review.

Conclusions of the Panel

Based on the findings from the literature review, the panel reached the following conclusions.

• In patients with cataract, the relationship between contrast sensitivity test results and functional impairment has not been adequately examined, although one study (Elliott, Hurst, and Weatherill, 1990) has demonstrated a correlation between binocular and better eye contrast sensitivity and patient-reported functional impairment due to vision. There is also published evidence in the low-vision literature, as summarized by the American Academy of Ophthalmology (1990), that suggests that contrast sensitivity test results are correlated with the degree of functional impairment in patients without cataract. These data and their relevance to the patient with cataract will be reviewed in a subsequent update of the guideline.

• Contrast sensitivity testing does not differentiate between visual loss due to cataract and visual loss from other causes.

• There is no commonly used contrast sensitivity test for which preoperative and postoperative results have been compared except the interferometer. In this case, only one published article exists (Morris, Klett, Gieser et al., 1991). It indicated that postoperative contrast sensitivity was accurately predicted in 10 of 15 cases. Inaccurate predictions occurred in patients with visual acuity worse than 20/200.

• In the absence of other studies comparing preoperative with postoperative contrast sensitivity results and in the absence of preoperative vs. postoperative assessments of functional impairment, the panel is unable to assess the clinical usefulness of information from contrast sensitivity testing, above and beyond that obtained from routine history and ocular examination, in determining whether a patient would benefit from cataract surgery.

Recommendations for Research

Further research should be undertaken to determine the clinical utility of contrast sensitivity testing as a source of valid information with respect to functional impairment due to cataract above and beyond that obtained through history and routine ocular examination.

Test Description

Glare is an impairment in visual function caused by the presence of a source of light located in the visual field. Patients with a cataract often complain of glare because cataracts and other opacities in the ocular media cause light entering the eye to be scattered, thereby producing glare. Glare testing attempts to reproduce the symptom of glare and to quantify the degree of visual impairment it causes. A typical patient with disabling glare complains of poor vision in well-lighted situations but may have nearly normal acuity when measured in a darkened room. Visual acuity may fall precipitously when retested in ambient light. Glare disability is generally determined by comparing a subject's visual acuity with and without the presence of a bright-light source directed at the patient's eye.

A variety of methods and devices for testing glare are described in the published literature. Some of the devices used for this purpose are simple and inexpensive, such as a penlight or room lights. More elaborate instruments costing hundreds of dollars, such as the brightness acuity tester (BAT), or thousands of dollars, such as the Miller-Nadler glare tester, are also available.

In the United States, glare disability testing is widely used to evaluate patients with cataract, in part because in many States, peer review organizations request the results of this test at the time of precertification for cataract surgery, particularly in patients with good visual acuity.

Literature Review Results

The results of the literature review are given here and summarized in Attachment 3.

Conclusions of the Panel

Based on the findings from the literature review, the panel reached the following conclusions.

• A number of devices are available for testing glare. It is difficult to compare them, however, because standards have not been established for glare source, background illumination, target configuration, and other factors.

• There is some evidence in the published literature that glare test results are reproducible in patients with cataract. More data are needed to evaluate the reproducibility of glare test results in patients with different types of cataract and different types of symptoms potentially attributable to glare.

• Glare disability symptoms are not specific to cataract. As with most tests of vision, glare disability testing is not able to differentiate between visual loss due to cataract and visual loss due to other causes.

• Several studies have adequately shown that abnormal glare test results improve after cataract surgery. Whether symptoms potentially attributable to glare and glare-related functional disability decrease postoperatively in such patients, however, has not been reported in the published literature.

• The correlation between glare test results and functional impairment in patients with cataract was examined in one study (Elliott, Hurst, and Weatherill, 1990). In that study, there was a correlation between glare disability, as measured by a reduction in visual acuity in the worse eye, and functional disability related to near vision and discrimination. The magnitude of these correlations was greater than the magnitude of the correlations between visual acuity and these functional disabilities. One cannot determine from the data that are reported, however, whether the differences in the magnitude of these correlations are either statistically or clinically significant.

• The correlation between glare test results and visual acuity is high in patients with cortical and nuclear cataracts and low in patients with PSC cataracts. This suggests that, if glare testing provides useful information regarding functional disability due to glare, it is most likely to be of value in patients with PSC cataracts.

• There are three ways that glare testing might be used in the context of a patient with functional impairment potentially due to cataract.

Application 1: As a stand-alone objective measure of functional impairment due to cataract.

The panel agrees that there is no evidence in the published literature that the test can be used as a stand-alone objective measure of functional impairment due to cataract justifying cataract surgery.

Application 2: As a source of valid information concerning functional impairment vs. visual impairment due to cataract, over and above information provided by the history and physical examination.

The panel agrees that there is no evidence from the published literature to support the use of the test as a source of valid information concerning functional impairment due to cataract, over and above that provided by the history and ocular examination.

Application 3: As a source of valid information on visual impairment that will assist the ophthalmologist in advising the patient regarding the suitability or deferral of surgery when used in conjunction with the history, ocular examination, and measurement of visual acuity.

The panel believes that glare testing may be useful in the clinical evaluation of patients who complain of glare, or who have symptoms potentially attributable to glare, and who have a cataract (particularly a PSC cataract), yet measure good Snellen acuity in the testing circumstances of an office. However, the published literature has not yet provided data that demonstrate that postoperative improvements in glare test results are associated with improvement in glare symptoms or with symptoms potentially attributable to glare.

Given the current state of knowledge, it is reasonable to perform a glare test as part of the evaluation of patients who complain of glare, or who have symptoms potentially attributable to glare, and who have a cataract (particularly a PSC cataract) and good Snellen acuity. However, glare testing should not be required by utilization review or quality assessment organizations, such as peer review organizations, as objective documentation of visual disability sufficient to justify the potential benefit of surgery.

The panel believes that the glare test is not useful in patients with cataract who do not complain of symptoms potentially attributable to glare, regardless of their visual acuity.

Recommendations for Research

Glare testing may be of value in corroborating glare symptoms in some patients. The panel recommends that more research be performed on glare testing to clarify its role in the evaluation of the patient with functional impairment potentially due to cataract.

Test Description

Tests of potential vision have been developed in an effort to determine whether individuals with obviously impaired vision have a potential to see well after cataract surgery (i.e., the significant cause of their visual impairment is cataract rather than other pathology). Two basic types of tests, subjective and objective, are available. Subjective tests require the individual being tested to respond to questions asked about visual stimuli that are presented, and objective tests do not.

Subjective tests include the suprathreshold pinhole device, Maddox rod test, laser interferometer, Guyton-Minkowski potential acuity meter, and a number of devices that use blue field entoptic images. Some of these are simple and inexpensive, such as entoptic imagery and the Maddox rod test, whereas others are more expensive because of the cost of the instruments needed to perform them, such as the laser interferometer and potential acuity meter (PAM). Objective tests are electrophysiologic tests in which the response to visual stimuli is measured electronically. Those evaluated in the literature include electroretinography and visually evoked potential.

Objective tests are generally more expensive than subjective ones because of the cost of electrophysiologic equipment and the expertise necessary to administer and interpret them. Such tests are generally not available in the private clinician's office. Instead, patients are usually referred to teaching institutions to obtain them.

Literature Review Results

The results of the literature review are given here and summarized in Attachment 4.

Conclusions of the Panel

Based on the findings from the literature review and panel discussion, the panel reached the following conclusions.

• Tests of potential vision can predict postoperative outcome reasonably accurately in eyes with a preoperative vision of better than 20/200 and media that are clear enough to confirm by examination that the posterior pole is normal. Evidence is lacking in the published literature that potential vision measurement increases the accuracy of the predicted outcome beyond that based on history and ocular examination alone.

• In eyes with opaque media and vision of 20/200 or worse, none of the tests of potential vision provides an accurate estimate of visual outcome after uncomplicated cataract surgery, although electrophysiologic tests may be useful in determining whether light signals are being received by the retina or brain (i.e., whether there is gross retinal disorganization).

• For eyes in which the posterior pole can be visualized, no conclusions can be drawn from the literature review about the influence of specific types of macular disease on the accuracy and value of tests of potential vision beyond what can be determined by ophthalmoscopic examination.

• There were no studies identified that address the issue of the predictive value of a collection or battery of potential vision tests in relation to postoperative visual acuity.

• There are three possible ways in which tests of potential vision could be used in evaluating a patient with functional impairment potentially due to cataract.

Application 1: As a stand-alone objective measure of expected visual outcome after surgery for cataract.

The panel concluded that tests of potential vision do not function as a stand-alone measure of predicted visual outcome after surgery for cataract, since they appear to be accurate only when:

• Visual acuity is 20/200 or better.

• The media are clear.

• The posterior pole is normal on clinical examination.

Application 2: As a source of valid information concerning the visual outcome vs. function after cataract surgery, over and above that provided by the history and ocular examination.

The panel concluded that tests of potential vision do not provide information over and above that provided by the history and ocular examination to justify their use as a basis for decisionmaking about the visual outcome after cataract surgery.

Application 3: As a source of valid information on visual outcome after cataract surgery that will assist the ophthalmologist in advising the patient about the potential value of cataract surgery when used in conjunction with the history and ocular examination.

The panel concluded that the available evidence in the published literature suggests that tests of potential vision do not assist the ophthalmologist in predicting the outcome of surgery when used in conjunction with history and ocular examination.

Tests of potential vision add nothing to the history and ocular examination of a patient with cataract when the posterior pole can be visualized and is normal. Tests of potential vision are not accurate in predicting visual outcome after surgery in a patient with cataract when the posterior pole cannot be visualized. It is impossible to determine from the literature whether any of the tests of potential vision is of value when the posterior pole can be visualized and macular disease is present.

Based on this literature review and clinical judgment, the panel concluded that a test of potential vision should not be included as a preoperative test in the routine management of patients with functional impairment due to cataract. The panel recognizes that there may be a subset of patients (patients with specific types of macular degeneration and clear media) in whom such a test might be of value, but this has yet to be shown.

Many ophthalmologists find potential acuity measurements reassuring in situations in which they are uncertain whether other diseases, particularly mild to moderate atrophic macular degeneration, might limit postoperative vision rehabilitation. However, there are no data that have substantiated the value of potential vision testing in this circumstance, even though such testing might be helpful.

Recommendations for Research

The panel recommends that properly designed studies be performed to assess the value of preoperative tests for potential vision in eyes with cataract and macular disease. These should include further investigation of the methods of potential vision testing that are already in existence. Reports of the results of evaluations of potential vision tests in patients with cataract should be more specific with regard to definition of media clarity, the presence of and type of macular disease, and the time at which patients are classified as to the presence of macular disease (i.e., preoperatively or postoperatively).

The panel also recommends that future studies address the usefulness of individual tests as well as a battery or collection of potential vision tests and that additional methods be developed to predict visual outcome after cataract surgery.

Test Description

Specular photographic microscopy is a research tool used to measure and record endothelial cell counts and to evaluate endothelial cell morphology. When endothelial cells are destroyed by disease or surgery, the remaining cells normally do not divide. Instead, they enlarge and spread out to cover the posterior corneal surface, thus decreasing the cell density (cell count) in a given area. Corneas with extremely low endothelial cell densities may decompensate, swell, and become cloudy with time. Although a precise lower limit cannot be defined, there is a variable lower limit of cell density in different patients below which the corneal endothelial cell layer cannot function adequately to maintain corneal clarity.

A cataract extraction procedure will usually result in some decrease in the endothelial cell density. Therefore, corneas with very low cell densities before cataract extraction are thought to be at greater risk for postoperative corneal decompensation and permanent corneal edema than are corneas with "normal" cell densities. Thus, there is a conceptual rationale for advocating the use of specular microscopy preoperatively to ascertain the cell density of the corneal endothelium and thereby assess a patient's risk of postoperative corneal decompensation.

The specular microscope provides a magnified view of a small area of corneal endothelial cells that is obtained by specular (mirrorlike) reflection. The specular image can be seen on routine slit lamp examination, but when a slit lamp is used, the magnification is less than when a specular microscope is used. Consequently, it may be difficult to discern individual cells with a slit lamp.

A specular microscope may be either a "contact" type (an applanating lens touches the cornea) or "noncontact" type (the microscope does not contact the eye but merely magnifies the image normally seen through the slit lamp). The contact specular microscope provides more magnification and is easier to focus, but it requires the use of a topical anesthetic on the eye. Both types of microscopes can be used by a trained technician.

Images of the endothelium seen with specular microscopy can be recorded on video tape or photographic film. The endothelial cell density and configuration can then be estimated from the video or photographic image. The cell density can also be estimated during examination with the slit lamp, but this technique is more difficult to perform and less accurate.

Quantitative analyses of the morphology of endothelial cells also can be performed by digitizing the image obtained with the specular microscope. A variety of morphologic measures can be defined, such as the mean area per cell or the variation in cell area.

Literature Review

Conclusions of the Panel

The results of the literature review failed to establish an association between the results of preoperative specular photography of the corneal endothelium and the outcome of surgery for cataract. The panel concluded that there is currently no evidence in the published literature or compelling rationale to support routine use of specular microscopy in patients for whom cataract surgery is being considered. Most patients at risk of corneal decompensation from surgery can be identified through history and clinical examination. There is no empirical evidence from the published literature that suggests that use of specular photographic microscopy in routine preoperative assessment adds information of value, beyond that gained through careful history and clinical examination, in deciding whether to proceed with cataract surgery or which procedure to perform.

The panel further concurred that, although the published literature does not provide evidence supporting use of specular photographic microscopy in the routine workup, there may be specific instances in which the endothelial cell count can contribute information pertinent to clinical decisionmaking. For example, there are patients with moderate degrees of endothelial disease and/or a history of previous intraocular surgery or intraocular inflammation for whom the test might be warranted. It is in these patients that a test to determine the status of the endothelium would be most helpful. However, the irregularity of the posterior surface layer in such patients may render the endothelium difficult to visualize. Further research on this subgroup of patients is warranted.

Literature Review

Conclusions

In most circumstances, cataract surgery is considered a nonemergency procedure. It is indicated when the cataract reduces visual function to a level that interferes with everyday activities of the patient. The severity of the interference can range from simple symptoms of glare disability to reduced ability to perform recreational activities and difficulty with reading, driving, employment, and performing other everyday activities.

The appropriateness of cataract surgery at each level of disability depends on the complete assessment of the overall visual function and the needs of the patient as well as adequate informed consent. Surgery for cataract is considered when medical, optical, and environmental measures have proved inadequate for the patient's visual requirements. The patient should make the decision to proceed with surgery on the basis of the ophthalmologist's recommendation and after considering subjective, objective, and educational criteria. However, the indication for surgery is founded on the patient's requirement for better vision and the patient's reasons for undergoing surgery. In almost all circumstances, surgery should not be performed solely because the cataract is present.

The ultimate decision regarding the desirability and timing of cataract surgery is determined by the patient and the ophthalmologist who is to perform the surgery. After a complete evaluation, the ophthalmologist confirms the subjective and objective findings of vision reduction related to a cataract.

Unfortunately, as discussed in Chapter 4, there are no objective, stand-alone measures of functional impairment due to cataract that might serve as precise indications for cataract surgery. The development of such measures is a matter of high priority.

Recommendations for Care

The search of the literature did not reveal any information helpful in elucidating precise indications for surgery. Thus, pending the results from future research, the panel recommends the adoption of the following guidelines based on the Preferred Practice Pattern, "Cataract in the Otherwise Healthy Adult Eye," produced by the American Academy of Ophthalmology (1989). Although it is principally directed toward the elective decision to undergo surgery, it also considers those circumstances in which cataract surgery is indicated because the health of the eye or the health of the person is endangered. The panel recognizes that scientific evidence is lacking from the published literature to support the validity of these guidelines. Nevertheless, the Preferred Practice Pattern, which was developed by an exhaustive consensus method, has been available for 3 years and has not been substantially challenged.

The indications for surgery are considered for various levels of visual impairment. A cutoff of Snellen acuity of 20/50 or worse is based on common State laws requiring better vision for drivers of motor vehicles.

Recommendations for Research

The panel recommends that research be directed toward a better understanding of functional impairment due to cataract to elucidate more precisely the appropriate indications for cataract surgery.

Background

Most patients undergoing cataract surgery are elderly persons, a population with a high prevalence of concurrent medical problems such as coronary artery disease, cerebrovascular disease, hypertension, diabetes mellitus, dementia, arrhythmias, chronic obstructive pulmonary disease, alcoholism, thromboembolic disease requiring anticoagulant therapy, and nutritional problems. In addition, these patients often have unique and commonly dysfunctional problems of aging, including situational difficulties and other problems, such as arthritis, as well as psychosocial, economic, and nutritional difficulties. Functional problems and their causes (often multiple and complex), defined as difficulties that interfere with daily routines, are often unappreciated when conventional histories and physical examinations are done. This part of the guideline addresses the appropriate preoperative medical and general evaluation of patients undergoing cataract surgery.

Literature Review

Conclusions of the Panel

The evidence in the published literature is sparse. The panel reached the following conclusions by consensus:

• The preoperative medical examination and appropriate testing should be done in all patients undergoing cataract surgery, whether the surgery is done in the hospital or elsewhere and regardless of the type of anesthesia to be used.

• Preoperative medical management should be guided by the patient's age, the presence of concurrent medical illnesses, the patient's use of medicine, and the patient's relative proximity to the location where surgery is performed.

• General preventive health measures (e.g., for hypertension, diabetes, smoking, and obesity) are suggested for all, including patients who otherwise may have infrequent encounters with the health care system. The panel believes that patients have the right to know what preventive measures are effective and appropriate in these circumstances, although they may choose to not take advantage of them.

• The preoperative medical evaluation should include screening for functional disability. Elderly patients should receive special screening of functional status, and particular attention should be given to the socioeconomic problems imposed by aging. This recommendation is in keeping with the panel's stated ultimate goal of improving the patients' overall long-term health and functional ability and the maintenance of autonomy.

• The panel agreed that the patient (or the patient and the ophthalmologist) can choose to have the preoperative medical evaluation for cataract surgery performed by a generalist or an appropriate subspecialist. This should be considered a separate service from the preoperative ophthalmologic evaluation in regard to the global surgery concept for cataract surgery.

• Areas of special importance to the individual such as cultural ethics and spiritual values should be taken into consideration before surgery, along with the individual's own assessment of the quality of life, for optimal preparation of the patient for surgery and recovery.

• The economic resources of the elderly person should be evaluated before surgery, since this often determines access to medical and personal care and influences options for living arrangements.

• Although the data are sparse, anticoagulation does not appear to pose a substantial risk for seriously complicating ophthalmic surgery, whereas discontinuing these drugs may impart some increased risk for new thrombotic events in the patient with preexisting cardiovascular, cerebrovascular, or thromboembolic disease.

In light of the sparse published literature available on this topic, the panel is unable to make explicit recommendations regarding the extent of the general medical evaluation and testing that should be done prior to cataract surgery. The panel recognizes, however, that this is an issue that cuts across the whole field of elective surgery and patient care.

Accordingly, the panel recommends that AHCPR develop guidelines for preoperative general medical evaluation and general medical testing of patients undergoing nonemergency surgery, including cataract surgery. Until such guidelines are established, the panel agreed that it should adopt a common sense approach to preoperative evaluation that would be sensitive to the medical judgment of a prudent physician evaluating an individual patient. Unfortunately, no consensus exists concerning the explicit goal of the preoperative medical evaluation of the patient scheduled for cataract surgery. However, the Preventive Services Task Force (1989) has recommended routine preventive measures for use in primary care settings that may be applicable to patients undergoing surgical procedures who do not ordinarily receive routine care. The preoperative medical evaluation can either be narrowly viewed as an occasion to evaluate the patient's health solely as it pertains to cataract surgery or be approached in the broader context of a unique opportunity to evaluate the patient fully and to diagnose potentially serious health, functional, and social problems unrelated to cataract surgery. The broader view is consistent with an ultimate goal of improving the overall long-term health and well-being of patients undergoing cataract surgery, instead of restricting the focus to improving vision. The panel favored the broader view but acknowledged that preventive health screening is a secondary issue that was not part of the panel's charge.

Recommendations for Research

Preoperative testing of cataract patients requires further study. Prospective studies should be designed and nationally funded to test the cost effectiveness of complete medical evaluation insofar as it prevents untoward intraoperative and postoperative events, uncovers previously unrecognized and treatable disease, and effectively disseminates preventive health measures.

Background

The choice and management of anesthesia technique may have a direct effect on the success of cataract surgical outcome. Many cataract patients are elderly, with multiple medical problems, particularly pulmonary and circulatory, and thus are at increased risk for morbidity during the perioperative period.

Anesthesia decisions that may influence outcome include the choice of general anesthesia vs. regional anesthesia with sedation and the choice from a variety of retrobulbar or peribulbar local anesthesia techniques available. The training and experience of the practitioner may influence the results and complication rates.

Finally, consideration must be given to the costs and benefits of various anesthetic management plans.

Literature Review

Conclusions From the Literature Review

Of the 94 articles identified by the National Library of Medicine computer search and other sources, only 9 met the search criteria and were further considered by content and methodologic reviewers for detailed analysis. Results of the review of these articles revealed that only three were randomized controlled trials. The remainder were either uncontrolled trials or clinical series. There were no well-designed prospective studies that compared general anesthesia vs. local anesthesia and anesthesia morbidity. No studies associated morbidity with the identity of the person monitoring or administering the local anesthesia injection. Two articles mentioned cost effectiveness in passing, but there was no study specifically analyzing in detail the costs and benefits of general vs. local anesthesia.

Only two articles (Redmond and Dallas, 1990; Smith, 1990) mentioned visual outcome. There was no information to associate visual outcome with choice of general or local anesthesia. Most articles noted complications of surgery or anesthesia but were of poor quality.

Recommendations for Care

The panel concurred that the choice of general or local anesthesia may affect visual outcome indirectly (i.e., through the effects of nausea, vomiting, or coughing after general anesthesia or sudden movement during local anesthesia) or directly. On balance, properly managed local anesthesia is simpler than general anesthesia, especially in patients with significant cardiac or pulmonary problems. Special monitoring techniques may be advisable in these patients. The panel concurred that the use of modern monitoring techniques is appropriate in cataract surgery, given the age of the patients and the high incidence of associated medical problems. Good monitoring might affect visual outcome indirectly if it prevents sustained hypertension, hypotension, or hypoxia.

The panel further believes that monitored anesthesia care by qualified anesthesia personnel is appropriate because the ophthalmologist is fully occupied in the surgical technique and therefore unable to deal with emergencies in a timely manner. Monitored anesthesia care includes physiologic monitoring with life-support systems available. The panel concurred that the administration of local anesthesia for cataract surgery is a skilled procedure and should be performed by an ophthalmologist or by another appropriately trained professional who has demonstrated competence in these techniques.

The panel agreed that there is a lack of studies in the literature addressing issues surrounding the administration of anesthesia for cataract surgery. The panel reached by consensus the following recommendations for care:

• Properly managed local anesthesia is preferred to general anesthesia and is appropriate unless precluded by extreme patient anxiety that does not respond to counseling or sedation, inability of the patient to cooperate with the surgical team, inability to provide satisfactory local anesthesia, known allergy to local anesthetic medications, and the presence of disorders that are best managed under general anesthesia (severe back pain, postural problems, etc.)

• Given the age of patients undergoing cataract surgery and the high incidence of associated medical problems, monitored anesthesia care provided by an anesthesiologist or anesthetist is justified and appropriate.

• Monitored anesthesia care should include the use of the following monitoring techniques: electrocardiogram, pulse oximetry, blood pressure, and respirations.

• The use of sedation drugs (reversible and with reduced side effects) is appropriate to minimize pain and discomfort while local anesthesia is being administered.

• Local anesthesia may be induced by the retrobulbar or peribulbar technique. Each has its own set of complications and advantages. The literature search did not identify evidence that one method was superior to others.

• The administration of peribulbar and retrobulbar anesthesia is a skilled procedure.

• It is in the best interest of the patient to have the safest local anesthesia possible administered by an individual fully trained in the procedure to be used.

• Because of the potential for extraocular complications (e.g., brain-stem anesthesia), peribulbar and retrobulbar anesthesia should be administered only to properly monitored patients with intravenous access established. There should be access to oxygen with assisted respirations via mask ventilation apparatus if necessary.

The panel also recommends that, in the patient's best interest, requirements for clinical competence to perform retrobulbar or peribulbar anesthesia be established to include training; supervision; knowledge of the appropriate anatomy, physiology, and pharmacology; and the ability to handle complications and consequences.

Recommendations for Research

The panel recommends that research be undertaken on unresolved questions concerning the impact of anesthesia on the outcome of cataract surgery, including cost and cost-benefit analyses.

Background

The dramatic revolution in cataract surgery over the last 15 years has been spearheaded by the adoption of microsurgical techniques. This includes the transition to the extracapsular cataract extraction (ECCE) procedure; the development of safe, effective IOLs; and the placement of the IOL behind the iris. The widespread acceptance of IOLs permitted satisfactory visual rehabilitation of patients with monocular cataracts who formerly would have been dependent on aphakic contact lenses. It is generally acknowledged that with these changes in technique, postoperative visual rehabilitation has improved to the point where surgical intervention is now appropriate at a much earlier stage of visual disability than had previously been possible.

Over the same period, modification of the surgical technique has continued on a variety of fronts. Most notable has been the introduction of phacoemulsification (PE) as a method of lens extraction. PE raises the expectation of enhanced safety and more rapid rehabilitation because of the reduced wound size needed. Alternative lens designs are also being explored to accommodate this decreased wound size and in an attempt to provide clear vision at both distance and near.

In this section, the type of surgical techniques (ECCE vs. PE) is considered in the context of effectiveness and complication rates. Lens design, secondary lens implantation, and other technical innovations are not within the scope of this guideline.

Literature Review

Results.

The systematic literature search identified 6,113 potentially relevant articles. Of these, 100 met the eligibility criteria established for this review. All of these articles underwent indepth methodologic and content reviews. The results of the literature review are as follows and are summarized in Evidence Tables K-1 to K-26 in Appendix K in the Guideline Report.

Overall, 57 studies examined visual acuity, 20 examined astigmatism, and 83 examined complications. On a study-specific basis, 4 studies examined only visual acuity, 31 examined only complications, 10 examined only astigmatism, 43 examined visual acuity and complications, none examined complications and astigmatism, and 7 examined visual acuity, complications, and astigmatism.

Among all the studies that examined visual acuity, the number of eyes studied ranged from 17 to 1,588. (The largest number of eyes studied by procedure was 756 for PE and 1,588 for ECCE.) Among all the studies that examined astigmatism, the number of eyes studied ranged from 50 to 503. (The largest number of eyes studied by procedure was 397 for PE and 503 for ECCE.) Among all the studies examining complications, the number of eyes studied ranged from 41 to 22,791. (The largest number of eyes studied by procedure was 2,704 for PE, 1,588 for ECCE, and 22,791 for a mixed group of PE and ECCE for which complications were reported for the entire group and not according to type of procedure used.)

The following is a summary of information on the principal outcomes and complications of cataract surgery. The data presented are exclusively from clinical series and observational studies. None of the studies that met the inclusion criteria involved random allocation of patients to various surgical procedures. Additionally, case mix (e.g., frequency of other significant eye disease in the study population), length of followup time, and definitions for specific complications varied tremendously by study. Therefore, great caution must be exercised both in examining specific rates as well as in pooling data across studies. Moreover, these methodologic limitations render any comparisons of outcomes between procedures (e.g., PE vs. ECCE) hazardous.

Question 1: Is there evidence that visual acuity after final refraction is better, no different, or worse when a cataract is extracted via standard ECCE vs. PE?

Of the articles that met the inclusion criteria, 57 examined visual acuity (Acheson, McHugh, and Falcon, 1988; Allen and Zhang, 1987; Azen, Hurt, Steel et al., 1983; Barrett, Beasley, Lorensetti et al., 1987; Barrett, Constable, and Steward, 1986; Brint, Ostrick, and Bryan, 1991; Cheng, 1987; Cinotti, Fiore, Maltzman et al., 1988; Cunliffe, Flanagan, George et al., 1991; Davison, 1984; Faulkner, 1987; Galand, Van Oye, Budo et al., 1985 ; Hara, 1986; Heslin and Guerriero, 1984; Komatsu, Kanagami, and Shimizu, 1989; Kooner, Cooksey, Perry et al., 1988; Kraff and Sanders, 1982; Kraff, Sanders, and Jampol, 1982; Kraff, Sanders, and Lieberman, 1983; Kraff, Sanders, Jampol et al., 1984 and 1985; Kratz, Mazzocco, and Davidson, 1979; Kratz, Mazzocco, Davidson et al., 1981a and 1981b; Levy and Pisacano, 1988; Liesegang, Bourne, and Ilstrup, 1990; Littlewood and Constable, 1985; Loh, Chew, Phua et al., 1985; Markoff, Levin, and Behar, 1985; Masket, 1989; McCaffrey and Lusby, 1986; Menapace, Skorpik, and Wedrich, 1990; Moschos, 1988; Naeser, Rask, and Hansen, 1986; Naylor and Sutton, 1989; Neumann and Cobb, 1989; Neumann, McCarty, Sanders et al., 1989; Noble, Hayward, and Huber, 1990; Pallin, 1987; Pedersen, 1990; Percival, 1987a and 1987b; Rich, Condon, and Percival, 1988; Ridgway, 1985; Shepherd, 1989a; Shimizu, 1988; Silvestri, Shepherd, and Johnston, 1989; Simcoe, 1981; Southwick and Olson, 1984; Stark, Maumenee, Datiles et al., 1983; Steinert, Brint, White et al., 1991; Story, 1988; Straatsma, Meyer, Bastek et al., 1983; Van Oye, Budo, Galand et al., 1986; Watts, 1986; Woodhams, Maddox, Hunkeler et al., 1984; Wright, Wilkinson, Balyeat et al., 1988). Visual acuity data were limited by a lack of documentation of preoperative data, including both visual acuity and documentation of ocular comorbid conditions that might limit postoperative acuity.

Table 5-1. Visual Acuity Following Cataract Surgery (more...)

Table 5-1. Visual Acuity Following Cataract Surgery

Percent of Eyes Reported To Be 20/40 or Better Postoperatively	Number (Percent) of Studies
>= 80	33 (100%)
>= 90	31 (94%)
>= 95	23 (70%)
>= 98	12 (36%)
100	6 (18%)

Source: Compiled from 57 articles, listed in the text, that addressed visual acuity.

Thirty-three of the 57 provided data on the percent of eyes without preexisting eye disease that achieved visual acuity of 20/40 or better (Acheson, McHugh, and Falcon, 1988; Allen and Zhang, 1987; Barrett, Beasley, Lorensetti et al., 1987; Barrett, Constable, and Steward, 1986; Brint, Ostrick, and Bryan, 1991; Cheng, 1987; Cunliffe, Flanagan, George et al., 1991; Galand, Van Oye, Budo et al., 1985; Heslin and Guerriero, 1984; Komatsu, Kanagami, and Shimizu, 1989; Kratz, Mazzocco, and Davidson, 1979; Kratz, Mazzocco, Davidson et al., 1981b; Levy and Pisacano, 1988; Markoff, Levin, and Behar, 1985; Masket, 1989; McCaffrey and Lusby, 1986; Menapace, Skorpik, and Wedrich, 1990; Neumann, McCarty, Sanders et al., 1989; Pallin, 1987; Pedersen, 1990; Percival, 1987a and 1987b; Rich, Condon, and Percival, 1988; Shepherd, 1989a; Shimizu, 1988; Silvestri, Shepherd, and Johnston, 1989; Southwick and Olson, 1984; Stark, Maumenee, Datiles et al., 1983; Steinert, Brint, White et al., 1991; Story, 1988; Straatsma, Meyer, Bastek et al., 1983; Van Oye, Budo, Galand et al., 1986; Wright, Wilkinson, Balyeat et al., 1988). Of these 33 studies, 31 (94 percent) reported that greater than 90 percent of eyes achieved acuity of 20/40 or better (Allen and Zhang, 1987; Barrett, Beasley, Lorensetti et al., 1987; Barrett, Constable, and Steward, 1986; Brint, Ostrick, and Bryan, 1991; Cheng, 1987; Cunliffe, Flanagan, George et al., 1991; Galand, Van Oye, Budo et al., 1985; Heslin and Guerriero, 1984; Komatsu, Kanagami, and Shimizu, 1989; Kratz, Mazzocco, and Davidson, 1979; Kratz, Mazzocco, Davidson et al., 1981b; Levy and Pisacano, 1988; Masket, 1989; Markoff, Levin, and Behar, 1985; McCaffrey and Lusby, 1986; Menapace, Skorpik, and Wedrich, 1990; Neumann, McCarty, Sanders et al., 1989; Pallin, 1987; Pedersen, 1990; Percival, 1987a and 1987b; Rich, Condon, and Percival, 1988; Shepherd, 1989a; Shimizu, 1988; Southwick and Olson, 1984; Stark, Maumenee, Datiles et al., 1983; Steinert, Brint, White et al., 1991; Story, 1988; Straatsma, Meyer, Bastek et al., 1983; Van Oye, Budo, Galand et al., 1986; Wright, Wilkinson, Balyeat et al., 1988). The results of these 33 studies are summarized in Table 5-1.

These results emphasize the excellent visual results that are expected in patients without significant ocular comorbidity.

Question 2: Is there evidence that the time to final refraction is shorter, no different, or longer when a cataract is extracted via standard ECCE vs. PE?

One controlled study (Heslin and Guerriero, 1984) suggested that the time to final refraction was 8 days shorter for PE vs. ECCE. Studies available for the preparation of this document do not permit a conclusion to be drawn that differences in visual acuity at time of final refraction exist between PE and ECCE.

Question 3: Is there evidence that the incidence of occurrence of more than 2 diopters of astigmatism at the time of final refraction is greater, the same, or less when a cataract is extracted via standard ECCE vs. PE?

Twenty articles examined astigmatism (Axt, 1987; Brint, Ostrick, and Bryan, 1991; Brown and Sparrow, 1988; Cory, 1989; Davison, 1984; Dixon, 1989; Gills and Sanders, 1991; Heslin and Guerriero, 1984; Jampel, Thompson, Baker et al., 1987; Kraff and Sanders, 1982; Maltzman, Cinotti, Horan et al., 1983; Masket, 1985 and 1990; Moschos, 1988; Naeser, Rask, and Hansen, 1986; Neumann, McCarty, Sanders et al., 1989; Pallin, 1987; Parker and Clorfeine, 1989; Shepherd, 1989a; Woodhams, Maddox, Hunkeler et al., 1984). Studies on residual postoperative astigmatism were limited methodologically by inconsistent reporting of preoperative astigmatism and the reporting of summary data for entire surgical populations, thereby not permitting the actual comparison of preoperative and postoperative astigmatism for individual patients. Additionally, there was extreme variation in the duration of time after surgery for which levels of astigmatism were reported. A commonly reported target for this outcome is a degree of astigmatism of less than or equal to 2 diopters postoperatively. Of 12 studies reporting on this target (Axt, 1987; Brint, Ostrick, and Bryan, 1991; Brown and Sparrow, 1988; Cory, 1989; Davison, 1984; Jampel, Thompson, Baker et al., 1987; Masket, 1985 and 1990; Moschos, 1988; Parker and Clorfeine, 1989; Shepherd, 1989b; Woodhams, Maddox, Hunkeler et al., 1984), 6, or 50 percent (Axt, 1987; Brown and Sparrow, 1988; Masket, 1985 and 1990; Parker and Clorfeine, 1989; Shepherd, 1989a) reported that greater than 90 percent of eyes had less than 2 diopters of astigmatism. The remaining six studies (Brint, Ostrick, and Bryan, 1991; Cory, 1989; Davison, 1984; Jampel, Thompson, Baker et al., 1987; Moschos, 1988; Woodhams, Maddox, Hunkeler et al., 1984) reported that at least 70 percent of the eyes had less than 2 diopters of astigmatism. Three of the four controlled studies (Heslin and Guerriero, 1984; Kraff and Sanders, 1982; Neumann, McCarty, Sanders et al., 1989) suggest that the change in astigmatism is less for PE than for ECCE. In the remaining study (Pallin, 1987), the change in astigmatism was not significantly different. These findings are consistent with the hypothesis that the absolute level of postoperative astigmatism decreases with the size of the surgical wound, since smaller incisions are typically used with PE vs. ECCE. However, these studies do not address whether the measured differences are of clinical significance to patients. Thus, available studies do not permit a conclusion to be drawn that clinically significant differences in astigmatism exist between PE and ECCE.

Question 4: Is there evidence that the incidence of certain ophthalmologic complications is greater, the same, or less when a cataract is extracted via standard ECCE vs. PE?

Table 5-2. Complications of Cataract Surgery

Table 5-2. Complications of Cataract Surgery

Complication	Rate (Percent)
Bullous keratopathy	< 0.3
Malposition or dislocation of the intraocular lens	< 1.0
Endophthalmitis (intraocular infection)	< 0.3
Retinal detachment	< 1.0
Clinically significant cystoid macular edema (postoperative swelling of the central retina)	< 3.0

Source: Compiled from 83 articles, listed in the text, that addressed rates of complications.

Eighty-three articles addressed rates of other complications (Acheson, McHugh, and Falcon, 1988 ; Allen and Zhang, 1987; Arnott and Condon, 1985; Arnott, Grindle, and Krolman, 1988; Azen, Hurt, Steel et al., 1983; Barrett, Beasley, Lorensetti et al., 1987; Barrett, Constable, and Steward, 1986; Born and Ryan, 1990; Bukelman, Hoffman, and Oliver, 1987; Cheng, 1987; Cinotti, Fiore, Maltzman et al., 1988; Coonan, Fung, Webster et al., 1985; Cunliffe, Flanagan, George et al., 1991; David, Tessler, Yagev et al., 1990; Davison, 1984 and 1988; Frezzotti and Caporossi, 1990; Galand, Van Oye, Budo et al., 1985; Hansen, Naeser, and Rask, 1987; Harris and Kogan, 1981; Heslin and Guerriero, 1984; Kattan, Flynn, Pflugfelder et al., 1991; Komatsu, Kanagami, and Shimizu, 1989; Kooner, Cooksey, Perry et al., 1988; Kooner, Dulaney, and Zimmerman, 1988; Kraff and Sanders, 1982 and 1990; Kraff, Sanders, and Jampol, 1982; Kraff, Sanders, Jampol et al., 1984 and 1985; Kraff, Sanders, and Lieberman, 1983; Kratz, Mazzocco, and Davidson, 1979; Kratz, Mazzocco, Davidson et al., 1981a and 1981b; Levy and Pisacano, 1988; Liesegang, Bourne, and Ilstrup, 1985 and 1990; Littlewood and Constable, 1985; Loh, Chew, Phua et al., 1985; Markoff, Levin, and Behar, 1985; Maynor, 1983; McCaffrey and Lusby, 1986; Menapace, Skorpik, and Wedrich, 1990; Milauskas, 1987 and 1990; Moisseiev, Bartov, Schochat et al., 1989; Moschos, 1988; Naeser, Nielsen, and Hansen, 1990; Naeser, Rask, and Hansen, 1986a and 1986b; Naylor and Sutton, 1989; Naylor, Sutton, Morrell et al., 1989; Neumann and Cobb, 1989; Neumann, McCarty, Sanders et al., 1989; Nishi, 1986; Noble, Hayward, and Huber, 1990; O'Donnell and Santos, 1985and 1990; Pedersen, 1990; Percival, 1987a and 1987b; Raines, Corridan, and O'Neill, 1989; Rich, Condon, and Percival, 1988; Ridgway, 1985; Sellman and Lindstrom, 1988; Severin and Severin, 1988b; Sheets, 1987; Silvestri, Shepherd, and Johnston, 1989; Simcoe, 1981; Simel, 1982; Smith, Stark, Maumenee et al., 1987; Southwick and Olson, 1984; Stark, Maumenee, Datiles et al., 1983; Steinert, Brint, White et al., 1991; Sterling and Wood, 1986; Story, 1988; Straatsma, Meyer, Bastek et al., 1983; Stur, Grabner, and Dorda, 1984; Taylor, Sachs, and Stern, 1984; Van Oye, Budo, Galand et al., 1986; Watts, 1986; Woodhams, Maddox, Hunkeler et al., 1984; Wright, Wilkinson, Balyeat et al., 1988). Although there was considerable variation among all studies in the rates of five major clinical complications, the rates obtained from the studies with the largest sample sizes are as shown in Table 5-2.

Available data in the published literature do not permit reasonable conclusions to be drawn that differences in the rates of these major complications exist between PE and ECCE. This is also true for other complications, including anterior chamber hemorrhage, hypopyon, chronic uveitis, iris trauma, increased open-angle intraocular pressure (IOP), increased closed-angle IOP, PSC opacification, zonular or posterior capsule rupture, loss of nuclear fragment into vitreous, vitreous hemorrhage, choroidal hemorrhage, retinal ischemia or infarction, angiographically proven cystoid macular edema, optic neuropathy, and ptosis.

Question 5: Does the literature provide data concerning the impact of cataract surgery on overall function of the patient?

No articles that met the inclusion criteria examined changes in visual function, as measured by everyday activities. Of these, one article (Masket, 1989) examined changes in contrast sensitivity and glare disability, which are outcomes related to visual function. Nine other articles (Applegate, Miller, Elam et al., 1987; Bernth-Petersen, 1981; Donderi and Murphy, 1983; Elam, Graney, Applegate et al., 1988 ; Hilbourne, 1975; Hill, 1982; Immonen, Tuominen, and Raivo, 1988; OCTET, 1987; O'Malley, Newmark, Rothman et al., 1989) that examined visual function or health status were excluded; these articles did not fulfill the selection criteria because the type of surgery or IOL was not specified. Most of these studies demonstrated that cataract surgery results in significant improvements in visual function and health status, such as everyday activities and emotional health, in the first year after surgery.

For a full description of the methodology and findings of the literature review, see Appendix K in the Guideline Report.

The scope of the review of the literature in this guideline addresses a comparison of the two forms of extracapsular surgery, ECCE and PE. The review, however, did not deal with the details of surgical techniques, adjunctive agents used in facilitating the procedures, use of instruments for cataract removal, selection of types and styles of IOLs, techniques of IOL implantation, and the consequences of applying such materials and methods.

Benefits and Harms of Cataract Surgery

Although no data precisely define the risks and benefits of cataract surgery, some estimates can be made based on literature reports of outcome and complications.

Harms of Cataract Surgery: Negative Outcomes.

Table 5-3. Estimated Rate of Negative Outcomes of Cataract (more...)

Table 5-3. Estimated Rate of Negative Outcomes of Cataract Surgery

>= 1:100	< 1:100	< 1:1,000	< 1:10,000	< 1:100,000
Glaucoma	Dislocated lens	Depression	Loss of eye	Death
Ptosis	Dilated pupils	Loss of vision	Chronic pain	Suicide
Intraocular hemorrhage	Endophthalmitis	Double vision	Psychosis
Problems with glare	Increased need for ocular medication		Expulsive hemorrhage
Cystoid macular edema	Retinal detachment		Systemic disease as a result of surgery
Adverse effects from drugs used in the treatment Increased ultraviolet exposure Need for further surgery	Bullous keratopathy

Note: Except for glaucoma, ptosis, increased ultraviolet exposure, and depression, the rate increases when there are comorbid conditions. Source: Compiled from reviewed literature and panel consensus.

Harms that may occur as a result of the expected surgery may be defined as negative outcomes. These include failure to achieve the expected positive outcomes or failure to relieve or improve the preoperative functional impairment as perceived by the patient, the patient's family, or the ophthalmologist who performed the surgery. In addition, negative outcome refers to the development of complications that either impair the patient's visual function or consume resources (Table 5-3). It should be noted that these complication rates are based on data obtained from the literature review and the consensus of the panel. Therefore, they should be considered only estimates.

The success rate of cataract surgery is reduced in the presence of comorbid ocular conditions. Again, data are lacking for precise estimates of this effect, but conditions such as corneal disease leading to loss of corneal clarity, glaucoma, and retinal disorders such as retinal detachment disease, macular degeneration, and diabetic retinopathy all contribute to loss of vision and, therefore, loss of the effect of the cataract surgery. The effects may be immediate (that is, proximate to the time of the surgical effect) or may become manifest a considerable period after the surgery is complete.

Conclusions From the Literature Review

The rate of visual improvement, degree of astigmatism, and incidence of other complications in studies with large sample sizes indicate that both ECCE and PE are safe and effective procedures. The panel felt that it was logical that small-incision (i.e., less than or equal to 4 mm) cataract surgery would cause less astigmatism than traditional cataract surgery, which is performed with a larger incision (10 mm). The panel also found some published evidence (Neumann, McCarty, Sanders et al., 1989) that is consistent with this hypothesis. However, the panel felt there were inadequate published data available as of the date of literature review to determine whether there were clinically significant differences in the amount of astigmatism that occurs in association with PE (particularly small-incision PE) vs. standard ECCE.

Conclusions of the Panel

Based on the evidence in the literature, the panel reached the following conclusions:

• Modern cataract surgery is safe and effective in restoring vision in patients with cataracts. Complication rates of modern cataract surgery are low. When complications do occur, however, they are often serious and vision threatening. It is of particular importance that the ophthalmologist who performed the surgery or is responsible for patient care during the postoperative period be prepared to diagnose and manage these conditions promptly and effectively. Effective treatment may require extensive additional complicated surgical procedures (e.g., glaucoma surgery, retinal detachment surgery, therapeutic vitrectomy, penetrating keratoplasty, or anterior segment revision). Prompt diagnosis and management of these conditions is a basic tenet of appropriate medical care.

• In the absence of comorbid conditions, a postoperative corrected visual acuity in the 20/40 to 20/15 range is a reasonable expectation for the vast majority of patients with functional impairment due to cataract. PE and ECCE surgery appear to be equally effective in restoring vision.

• The motivation for using PE in cataract surgery is enhanced safety coupled with a more rapid rehabilitation following the procedure. The rationale is that the smaller wound promotes less likelihood of wound dehiscence, more rapid healing, and reduced postoperative astigmatism. In addition, this may be advantageous in some eyes with comorbid conditions. Although these concepts are intuitively appealing, it is not possible to determine from the published literature, in a definitive manner, whether the use of the PE technique leads to a more rapid functional rehabilitation of the patient; whether the use of PE leads to less induced postoperative astigmatism; or whether specific or overall complication rates associated with PE are better, worse, or unchanged compared with the rates associated with the standard extracapsular procedure.

• Studies in the published literature demonstrate that cataract surgery results in significant improvement in visual function and overall functional status in the first postoperative year. It is not possible, however, to determine whether the use of PE over the standard extracapsular procedure enhances the outcome when measured by reduction or elimination of functional impairment due to cataract.

Recommendations for Care

The questions raised in this portion of the literature review are central to the debate concerning technical innovations in surgery, namely the indications, contradictions, complaints, benefits, and risks of one technique as opposed to the other.

In the absence of specific guidance from the published scientific literature, the panel recommends that ophthalmologists use their best judgment in selecting the surgical techniques for individual patients with cataract. This decision regarding the appropriate technique should be made by the ophthalmologist who is to perform the surgery according to his or her training and experience and after discussion with and explanation to the patient.

It is the responsibility of the ophthalmologist who is to perform the surgery to do the following:

• Ensure that the patient has had a general medical history and physical examination as appropriate to the planned surgery and the type of anesthesia.

• Ensure that the appropriate keratometry and A-scan measurements have been performed, if an IOL is to be implanted.

• Select the appropriate IOL power after discussion with the patient, if an IOL is to be implanted.

• Review the results of presurgical and diagnostic evaluation of the patient and discuss the findings with the patient or, in appropriate cases, with another responsible adult acting for the patient.

In considering all possible benefits and harms, comorbid conditions must be taken into account. The degree to which they are treatable or being treated, or that surgery is modified to account for them, will influence the outcome. Overall, in the presence of these conditions, the success rate of the surgery is reduced from the overall high level of expected outcome in the eye without comorbid conditions. Visual loss with these comorbid conditions may occur even without surgery.

Recommendations for Research

The panel recognizes that the literature lags behind current practice in evaluating changes in clinical practice such as surgical technique. As a result, data on effectiveness and complications reported in the literature may not apply to current clinical practice.

The panel recommends that research be undertaken to develop innovative approaches for evaluating surgical outcomes so that timely data can be derived.

Background

When an individual who has already had cataract surgery in one eye develops a vision-impairing cataract in the second eye, the patient and the ophthalmologist are confronted with the same issues regarding the decision for surgery that were present during the development of the cataract in the first eye. This section of the guideline addresses the indications for cataract surgery in the second eye and the timing of the surgical intervention.

Literature Review

Conclusions From the Literature Review

None of the papers identified in this literature search contained information relevant to the questions posed. No precise indications for cataract surgery on the second eye were identified. The majority of these studies were on aphakic patients and, thus, were of doubtful relevance to the modern pseudophakic eye in patients. Several studies addressed outcome following bilateral surgery. Cost-benefit issues to the patient and the community were not addressed. All these papers contained a variety of methodologic defects, which considerably lessened the impact of the conclusions drawn by the authors; these are summarized in the comments of the evidence table.

The search of the literature did not reveal answers to the questions specified by the panel regarding surgery on the second eye.

Conclusions of the Panel

Although the studies concerning indications and outcomes for surgery on the second eye had significant limitations, they nevertheless provided some strong suggestions about the need for such surgery. The disabilities caused by a visual deficit in the second eye are significant (e.g., loss of binocularity and stereopsis). Since measures of visual function such as acuity, stereopsis, and visual field are all enhanced by binocular vision, the panel felt that these facts strongly support the potential benefit of surgery in the second eye. The existence of anisometropia and often aniseikonia due to disparate refractive errors, as well as the unequal visual acuity due to the presence of the cataract in the second eye, are factors that bring both patient and surgeon to the decision to operate on the second eye, even after successful visual rehabilitation of the first eye.

Costs and benefits were touched on only in some of the papers. Nevertheless, as with the suggestions for indications and outcomes, there were a few conclusions. Restoration of binocularity, especially in working individuals, was helpful in restoring productive people to their optimum status, thereby indirectly stimulating the economy and eliminating disability benefits. Also, in certain circumstances, performing surgery on both eyes in the same operating session was considered to be economically justified, although this runs the very real risk of catastrophe if there is an unrecognized problem with unsterile instruments or materials used in both eyes. Once again, these data have limited statistical support.

Recommendations for Care

In light of the lack of scientific documentation, the panel offers the following conclusions by consensus after considering the policy statement from the American Academy of Ophthalmology (1991) regarding surgery on the second eye.

When a patient with functional impairment due to bilateral cataracts has undergone surgery in one eye, surgery in the second eye is justified and appropriate when the subjective, objective, and educational criteria (outlined in the section on indications for surgery) are met. The patient and the ophthalmologist should then proceed to evaluate the need for cataract surgery in the second eye, as outlined in the section on surgical techniques and complications. As part of this evaluation, the patient should be educated about the possibility of a subsequent complication in the first eye. In the event a patient initially decides to defer surgery on the second eye, the opportunity for surgery in the future should not be denied.

There are no scientific data to indicate the optimal time interval for surgery on the second eye. The panel agrees that judgment regarding this time interval should be based on the following factors. In no case should surgery be done on both eyes at the same surgical procedure.

• The patient is able to provide informed consent for surgery on the second eye after evaluating the visual results and postoperative course of surgery on the first eye.

• Adequate time has passed to detect and treat the most immediate vision-threatening complications of cataract surgery.

• Vision in the operated eye has recovered sufficiently that the patient is not at risk of injury due to functional impairment during second eye cataract surgery and the immediate postoperative period.

• In the event that vision has not recovered or is not recoverable, there is time to arrange for adequate assistance so the patient is not at risk of injury due to functional impairment following second eye cataract surgery.

The following factors may influence the patient's and surgeon's judgment regarding the timing of surgery on the second eye:

• The distance from home of the nearest available facility for surgery and appropriate postoperative care.

• The patient has a need (e.g., occupational) for good binocular vision within a limited timeframe after the first eye surgery.

• The patient is symptomatic due to postoperative anisometropia.

Early spectacle correction or decrease in the duration of the postoperative course alone, however, is not adequate justification for performing surgery on the second eye before the patient and the ophthalmologist have had sufficient opportunity to evaluate the results from the surgery on the first eye.

An exception to these indications is the special case where the opposite eye has no useful vision. In this case, the decision for surgery is determined by the degree of vision reduction at the time the patient enters into the evaluation process. In some cases, surgery may be delayed because of the greater potential for total blindness in the event of a serious complication of surgery. It is then the obligation of the ophthalmologist to inform and educate the patient about the potential risk of total blindness. Although the decreased visual acuity and level of disability may fall well within the guidelines for cataract surgery, the worse the vision is in the fellow eye, the greater the need is for caution in considering cataract surgery in a patient's only seeing eye.

Recommendations for Research

It is clear from a review of the literature that the questions surrounding the decision to operate on the second eye have received insufficient attention in the scientific literature. The panel recommends that research be undertaken to investigate the benefits of surgery on the second eye as opposed to the benefits of surgery on one eye only, and the optimum time for that surgery to be performed when the patient has functional impairment from binocular cataracts. The cost-benefit issues related to this topic are also important and should be analyzed.

Methods

The purpose of the literature review was to determine if there was evidence in the published literature to support or refute an association between the outcome of cataract surgery and the care provided in the postoperative period.

Results

The literature search identified 36 potentially relevant articles. Upon further review, 15 of these articles were found to be relevant. These 15 articles underwent indepth content and methodologic review. The results of the literature review are as follows and are summarized in Evidence Tables M-1 to M-3 in Appendix M in the Guideline Report.

Conclusions From the Literature Review

The literature review did not provide answers to any of the panel's questions dealing with postoperative care and outcome. However, direct evidence was provided about the importance of postoperative examination on day 1 and weaker evidence for the importance of the examination around the second or third week.

(See Appendix M in the Guideline Report for a full discussion of the literature review.)

Patient Education

The ophthalmologist who performs the surgery has an obligation to educate and instruct the patient regarding the following: appropriate signs or symptoms of possible complications, eye protection, activities, medications, required visits, and details for access to emergency care. The patient likewise has an obligation during the postoperative phase to follow the advice and instructions of the surgeon and to notify the surgeon promptly if problems occur.

Patient's Condition at Discharge

Patients undergoing outpatient cataract surgery will normally be discharged from the facility to their home or to another accommodation that is conveniently close so that emergency care can be provided if needed. Criteria for discharge after ambulatory surgery include:

• Stable vital signs.

• Return to preoperative mental state.

• Absence of nausea.

• Absence of significant pain.

• Availability of an escort.

• Review, with the patient or escort, of postsurgical care until the first postoperative visit on the day following surgery, including relief of pain, activity level permitted, and access to emergency care if needed.

• Prearranged followup appointment.

• Written postoperative instructions.

• Suitable environment.

• Adequate home care support.

Postoperative Hospitalization

Hospitalization after surgery may be unplanned or planned.

Operative complications of an ocular or medical nature are possible indications for unplanned postoperative hospitalization. Postoperative ocular complications can include hyphema, infection, wound dehiscence, endophthalmitis, uncontrolled elevated IOP, threatened or actual expulsive hemorrhage, retrobulbar hemorrhage, severe pain, or other ocular problems requiring immediate management or careful observation.

Medical complications can include cardiac instability, respiratory instability, a cerebrovascular episode, diabetes mellitus requiring immediate management, uncontrolled nausea or vomiting, acute urinary retention, acute psychiatric disorientation, or other medical conditions requiring immediate management or careful monitoring.

Indications for planned postoperative hospitalization are as follows:

• Medical conditions are present that require prolonged postoperative observation by a nurse or skilled personnel.

• Best correctable vision in the unoperated eye is 20/200 or worse.

• Patient is mentally debilitated, diagnosed as mentally ill, or functionally incapacitated so that a risk of injury exists in the immediate postoperative period.

• Physical disability prevents satisfactory immediate postoperative care.

Postoperative Visits

The frequency of examination during the postoperative period is predicated on the need to:

• Diagnose and provide the most efficient treatment for complications when they arise.

• Provide appropriate postoperative care as healing proceeds.

• Educate and support the patient during the postoperative period.

Fortunately, serious complications occur infrequently with modern cataract surgery (see Anesthesia, Chapter 5). However, they occur unpredictably and when untreated may have a devastating effect on the outcome of surgery. In order to minimize the risk that such complications will go unrecognized and, therefore, untreated, a schedule of visits is recommended by the panel based on the following requirements:

• The earliest practical assessment of the effects of the surgery.

• The diagnosis and treatment of immediate complications of surgery.

• The prompt diagnosis of other complications that could be potentially devastating to vision, particularly infection and glaucoma. Both of these complications may occur at any time during the postoperative period. Although the most acute bacterial infections tend to present within the first few days of surgery, less virulent but still potentially devastating infections with other bacteria and fungi may develop in the succeeding weeks and months.

The frequency of normal followup for a patient without signs or symptoms of possible complications is:

• First visit: day after surgery.

• Second visit: approximately 1 week after surgery.

• Third visit: approximately 3 weeks after surgery.

• Fourth visit: approximately 6-8 weeks after surgery.

More frequent postoperative visits are indicated if unusual findings or complications occur.

Postoperative Examinations

The components of postoperative examinations include the following:

• Visual acuity each visit.

• IOP measurement each visit.

• External examination each visit.

• Slit lamp examination each visit.

• Patient counseling and education each visit, unless the patient's condition does not allow it. (This should include information about progress toward healing, medication instructions, level of activity permitted, symptoms requiring emergency care, and access to emergency care.)

• Ophthalmoscopy. (A dilated fundus examination to include the peripheral retina should be done at least once during this postoperative period.)

The timing and frequency of refraction will depend on patient needs, the amount of astigmatism, and the stability of the measurement. Sutures may be cut or removed by the ophthalmologist for the reduction of astigmatism. Usually, optical correction can be prescribed 6-12 weeks after surgery.

Long-Term Followup

Patients should be informed of the need for periodic eye examinations and of the possible need for YAG capsulotomy if a posterior capsular opacification develops.

Methods

The purpose of the literature review was to determine if there was evidence in the published literature to support or refute an association between the outcome of cataract surgery and factors affecting the rehabilitation of the patient during the postoperative period. (For a full description of the review process, see Appendix N in the Guideline Report.)

Results

The questions identified by the panel are as follows.

Question 1: Is there evidence to support or refute an association between outcome of cataract surgery and delivery of postoperative care at home?

Question 2: Is there evidence to support or refute an association between outcome of cataract surgery and preoperative and postoperative patient and family education and counseling?

Question 3: Is there evidence to support or refute an association between outcome of cataract surgery and functional status (physical and mental) of patients at the time of surgery?

Question 4: Is there evidence to support or refute an association between outcome of cataract surgery and financial status?

Question 5: Is there evidence to support or refute an association between outcome of cataract surgery and cultural, religious, and ethnic factors?

Question 6: Is there evidence to support or refute an association between outcome of cataract surgery and the identity of the person involved in providing postoperative rehabilitation (e.g., family member, ophthalmic nurse, registered nurse, medical social worker, or social agency)?

Question 7: Is there evidence to support or refute an association between outcome of cataract surgery and the costs and benefits of formal rehabilitation programs?

Thirty-two articles underwent indepth reviews. Although they all addressed aspects of the care of patients with cataract, none satisfied the inclusion criteria as specified by the panel.

One study (Graney, Applegate, Miller et al., 1990), which failed to meet the inclusion criteria, examined preoperative predictors of surgical success in patients with cataract and retinal disease; the authors found the availability of a helper in the home was not a prognostic indicator. The description of this portion of the study and the data were insufficient to allow an assessment of the implications of this finding.

Conclusions From the Literature Review

This literature search failed to identify evidence in the published literature to address the questions posed by the panel concerning rehabilitation of the patient undergoing cataract surgery.

Compliance

Cataracts in adults tend to develop bilaterally, so poor vision in the unoperated eye may increase the degree of difficulty in instilling eyedrops. Conditions associated with the aging process, such as rheumatoid arthritis and diabetes, can result in peripheral nerve dysfunction and inhibit the medication instillation (Donnelly, 1987). Other sensory changes in old age may increase the patient's difficulty in understanding treatment and how to comply with instructions (Smith and Drance, 1984). Problems with speech discrimination and the increased time needed to process oral information may render rapid speech unintelligible.

Patient Education

Careful preoperative assessment of the abilities of the patient and family to understand and comply with instructions is critical to ensuring adequate postoperative care and is the responsibility of the surgeon and his or her staff. Education for postsurgical care most appropriately begins preoperatively. However, the focus of diagnosis, surgical procedure, and visual prognosis may provide too much information for the patient to absorb. Some patients are shocked when they learn they have cataracts, and others do not even realize the extent of the visual impairment, since the deterioration is usually a gradual process (Low, 1978). Hence, preoperative education is initiated during a difficult period and may be of limited value. The postoperative cataract patient, discharge instructions in hand, may not be able to distinguish the normal from the abnormal response and may decline to contact the physician because of feelings of embarrassment or lack of understanding. The patient may have a written document listing the postoperative instructions but may not be able to read it because of reduced vision or other physical or mental problems (Smith and Drance, 1984). This may prevent the treatment from being accomplished successfully. Referral to a home health agency in such circumstances is appropriate for further education and evaluation of a patient's ability to follow discharge instructions.

Management of Postoperative Complications

Although serious complications after modern cataract surgery are now infrequent, their occurrence is unpredictable. Lack of provisions for immediate intervention could result in an adverse surgical outcome, particularly for the patient living alone.

Coexisting medical problems, such as arthritic deformities, insulin-dependent diabetes, hypertension, cardiac disease, drug or alcohol addiction, mental illness, dementia, severe depression, or acute grief, create a complex situation for the postoperative patient. The physical limitations from a preexisting condition may limit or prevent the patient from properly complying with the required postoperative regimen. Thus, there is the potential for ineffective treatment or overdosing of medications (Hunt, 1991). It may be difficult for patients to identify labels on eyedrops because of their altered visual status postoperatively. The use of certain ophthalmic medications by patients concurrently treated with other drug therapy heightens the potential for serious adverse systemic reactions (e.g., topical beta-blocking agents added to systemic beta blockers). In the patient with delayed recovery or unrecognized postanesthetic complications, premature discharge without appropriate planning and education could be fatal.

Economic Factors

In addition to the diagnostic and pretreatment considerations in older patients, cataract surgery may also have an adverse economic impact on patients and their families. Many patients are retired persons living on a fixed income. With the increased cost of living, some are pauperized, and others suffer significant deprivation.

Cataract surgery can present multiple problems for many patients who are ill equipped to deal with them. If they are among the "frail elderly," their needs are multiplied in the immediate postoperative period. They may need a stay in a motel for a night before surgery and a night or two after surgery. They may need assistance in the home for ambulation, transportation, meal preparation, administration of medication, and so on. These services may be unavailable for economic reasons and may or may not be reimbursed by Medicare, depending on the circumstances.

Environmental Factors

Postoperative rehabilitation may be profoundly influenced by the patient's home environment (e.g., hazards such as broken steps, obstructed pathways, and lighting) and other factors, such as location in a high-crime area, lack of transportation, and distance from medical care support services.

Cultural and Ethnic Factors

The diverse cultural and ethnic composition of American communities can create barriers to the effectiveness of the health care provider. There is evidence that race may be a factor in determining access to health care (Sommer, Tielsch, Katz et al., 1991). Recognizing the mores and belief systems of the patient aids in developing an appropriate plan for care ().

A substantial barrier to patient care is the inability to communicate with the health care provider. Failure to convey information effectively to non-English-speaking patients may adversely affect the rehabilitative outcomes. The needs of deaf patients should be accommodated to ensure that the information related is understood.

Psychosocial Factors

Learning how elderly people function in their daily lives is essential to understanding and caring for them. Their hearing and vision may be impaired, their responses may be slow, and they often have chronic physical or mental illnesses with associated discomforts and difficulties in ambulation. For several reasons, elderly people may not report their symptoms. Often, they may not want to burden their family members or friends who might be their sole mode of transportation. They may be afraid or embarrassed to do so, they may be trying to avoid medical expenses or the discomforts of diagnosis and treatment, they may think that their symptoms are merely a part of the aging process, or they may have simply forgotten about their symptoms (Bates, 1987).

A significant occurrence among the aged is the tendency toward isolation: the spouse may not be alive, the extended family may live at a distance, and/or the physical environment may not be conducive to venturing outside. The fear of losing independence may deter the patient from seeking assistance from any agency before surgery. The return home postoperatively may intensify feelings of loneliness and isolation, compounded by the anxiety of the altered visual state, delayed recovery from anesthesia, and the anticipation of compliance with postoperative instructions. Referral for counseling should be made when indicated. Referral to local support groups -- such as the National Society to Prevent Blindness, Inc. (800-331-2020) -- should also be considered.

Other sensory losses cause increased difficulty in coping with the modified lifestyle. The patient with reduced vision in the unoperated eye may experience increased anxiety because of the perceived inability to dial the telephone or deal with meal preparation and other simple everyday activities. The patient may even develop psychosis due to sensory deprivation and require psychiatric consultation.

The postoperative cataract patient may have responsibilities not readily recognized by the health care team, including that of caregiver for an incapacitated spouse or child. The need to continue this status may be the principal reason for undergoing the surgery. The reality that the patient is now dependent postoperatively may create acute anxiety and an inability to cope.

Methods

The purpose of the literature review was to identify and review those articles that contained information on PCO and YAG capsulotomy in relation to functional impairment due to cataract. (For a full description of the literature review process, see Appendix O in the Guideline Report.)

Results

The results of the literature review are as follows and are summarized in Evidence Tables O-1 to O-5 in Appendix O in the Guideline Report.

The computer search identified 138 papers thought to be relevant to the topic. Three additional papers thought to be relevant to the topic were identified from a variety of sources, which brought the total article count to 141. Seventy-eight were selected for further review because the abstract of the article suggested a relevance to the subject. Of the 78 articles, 2 pairs were found to be duplicates; one of each pair was excluded, leaving a total of 76 articles. One other paper (Javitt, Tielsch, Canner et al., 1992), the product of a study by the Cataract Patient Outcomes Research Team (PORT), was accepted for review, making a total of 77 out of 142 papers. The basis for inclusion of Javitt, Tielsch, Canner et al. (1992) was the potential importance of the data despite the failure to meet inclusion criteria (i.e., unpublished manuscript). This paper was published subsequent to the review. A total of 65 articles were excluded. Of the 77 included articles, 2 pairs contained identical data (Durham and Gills [1985]/ Shah, Gills, Durham et al. [1986] and Pollack, Brown, Crandall et al. [1989]/ Pollack, Brown, Crandall et al. [1988]).

A review of the 77 papers showed that very few of the studies were designed to answer the questions the panel was asked to address, and most suffered from limitations common to retrospective studies or methodologic defects that severely constrained the conclusiveness of the results. These design and methodologic problems are discussed within the context of each question. In spite of these shortcomings, the reviewers felt that there was sufficient clinical information in these papers to allow for some conclusions and to provide a basis to stimulate future studies.

Since many of the studies provided information on more than one of the five questions addressed by the panel, the sum of the total number of studies for each question is greater than 77. A critical review of the available information on each question follows.

Question 1: Is there evidence on rates of occurrence of visually significant PCO?

Table 8-1. PCO Incidence After Cataract Surgery

Table 8-1. PCO Incidence After Cataract Surgery

Source	Cataract Surgery	Average Followup (Months)	PCO Incidence Information
Naeser, Rask, and Hansen, 1986a	ECCE/IOL	4	3.0 percent PCO requiring YAG
Naeser, Rask, and Hansen, 1986b	--	--	12.1 percent moderate PCO without YAG
Sellman and Lindstrom, 1988	ECCE/IOL	12	7.1-16.1 percent moderate/severe Elschnig pearl migration; 2.4-4.4 percent capsular fibrosis
Watts, 1986	ECCE/IOL	17	2-4 percent capsular membrane thickening
Kooner, Dulaney, and Zimmerman, 1988	ECCE/IOL	18	15 percent posterior capsule haze
Van Oye, Budo, Galand et al., 1986	ECCE/IOL	24 (minimum)	9.8 percent requiring YAG; 20.1 percent PCO without YAG
Story, 1988	ECCE/IOL	32	4.1 percent requiring discission due to VA <20/40 or PCO-related symptoms
Moisseiev, Bartov, Schochat et al., 1989	ECCE or ECCE/IOL	48 (minimum)	41 percent PCO requiring capsulotomy
Frezzotti and Caporossi, 1990	ECCE or ECCE/IOL	60 (minimum)	7.7-14.2 percent PCO

Note: ECCE = Extracapsular cataract extraction. IOL = Intraocular lens. PCO = Posterior capsular opacification. VA = Visual acuity. YAG = Yttrium aluminum garnet.

Twelve unique articles addressed this question (Allen and Zhang, 1987; Frezzotti and Caporossi, 1990; Kooner, Dulaney, and Zimmerman, 1988; Moisseiev, Bartov, Schochat et al., 1989; Moschos, 1988; Naeser, Rask, and Hansen, 1986a [identical data reported in Naeser, Rask, and Hansen, 1986b]; Sellman and Lindstrom, 1988; Story, 1988; Straatsma, Meyer, Bastek et al., 1983; Sudhakar, Ravindran, and Natchiar, 1989; Van Oye, Budo, Galand et al., 1986; Watts, 1986). Undefined outcome, patient dropout, undefined PCO, and lack of adjustment for variation in followup time made the rate of occurrence of PCO difficult to assess. In the absence of a definition of, or a variation in the definition of, a visually significant PCO, it is likely that there is a wide variation in what is considered visually significant. Most of the studies lack a definition of this outcome. Many studies simply refer to the time of YAG capsulotomy as a surrogate for this outcome, which may be quite inaccurate. Followup time ranged from 2 weeks to 5 years, with capsular opacification rates varying from 2 to 16 percent at 1 year and up to 41 percent at 4 years. The data suggest that the incidence of visually significant PCO increases in direct proportion to postoperative followup time (Table 8-1). One paper (Frezzotti and Caporossi, 1990) suggested that patients younger than 40 years had a higher rate of visually significant PCO.

Question 2: Is there evidence on timing and rates of performance of YAG capsulotomy?

Table 8-2. Incidence of YAG Capsulotomy After Cataract (more...)

Table 8-2. Incidence of YAG Capsulotomy After Cataract Extraction

Source	Cataract Surgery	Average Followup (Months)	YAG Incidence Information (Percent)
Naeser, Rask, and Hansen, 1986a[1]	ECCE/IOL (N=66 eyes)	Mean=4	3
Milauskas, 1987	ECCE/IOL (N=732 eyes)	Mean=9	7.0-27.9
Van Oye, Budo, Galand et al., 1986	ECCE/IOL (N=214 eyes)	24 (minimum)	9.8
Downing, 1986	ECCE/IOL (N=757 eyes)	12-62	11.2
Maltzman, Haupt, and Cucci, 1989	ECCE/IOL (N=187 eyes)	Mean=24	15.1-20.8
Davison, 1988	ECCE (N=3,120 eyes)	At least 12	16.1
Shepherd, 1989b	ECCE/IOL (N=228 eyes)	12 (all eyes)	4.8-16.5
Coonan, Fung, Webster et al., 1985	ECCE (N=842 eyes)	Mean=32 (at least 12)	16.7
Javitt, Tielsch, Canner et al., 1992	ECCE (N=55,103 eyes)	Mean=24 (range, 12-36)	24
Wright, Wilkinson, Balyeat et al., 1988	ECCE/IOL (N=50 eyes)	6 (all eyes)	38
Fourman and Apisson, 1991	ECCE/IOL (N=732 eyes)	Not reported	53

[1] Identical data reported in Naeser, Rask, and Hansen, 1986b.

Note:ECCE = Extracapsular cataract extraction, IOL = Intraocular lens, YAG = Yttrium aluminum garnet.

The performance of YAG capsulotomy is an objectively identifiable endpoint, unlike the more subjective determination of the onset of visually significant PCO; however, there is wide intersurgeon variation in the criteria used to determine when this procedure is warranted. Lack of information on these criteria or use of subjective criteria (such as the surgeon's determination that the PCO was "significant") is the most critical unknown in the 30 studies that include information on the timing and rates of performance of YAG capsulotomy (Aron-Rosa, 1985; Brown, Thomas, Belcher et al., 1985; Burratto, Ricci, and Vitali, 1985; Capone, Rehkopf, Warnicki et al., 1990; Chambless, 1985; Coonan, Fung, Webster et al., 1985; Davison, 1988; Downing, 1986; Durham and Gills, 1985 [identical data reported in Shah, Gills, Durham et al., 1986]; Flohr, Robin, and Kelley, 1985; Fourman and Apisson, 1991; Gardner, Straatsma, and Pettit, 1985; Javitt, Tielsch, Canner et al., 1992; Knolle, 1985; Koch, Liu, Gill et al., 1989; Leff, Welch, and Tasman, 1987; Lewis, Singer, Hanscom et al., 1987; Liesegang, Bourne, and Ilstrup, 1985; Maltzman, Haupt, and Cucci, 1989; Maltzman, Haupt, and Notis, 1989; Milauskas, 1987; Naeser, Rask, and Hansen, 1986a; Richter, Arzeno, Pappas et al., 1985a; Schubert, 1987; Shepherd, 1989b; Slomovic, Parrish, Forster et al., 1986; Steinert, Puliafito, Kumar et al., 1991; Stern, Taylor, and Bernstein, 1985; Van Oye, Budo, Galand et al., 1986; Wright, Wilkinson, Balyeat et al., 1988). The study by Javitt et al. (Javitt, Tielsch, Canner et al., 1992) indicates a wide range of YAG capsulotomy rates per person-year across the United States (2.5-27 percent), which is attributed to a lack of consensus on timing and indications for the procedure. There is a need to explain the twofold-to-sevenfold increase in rates of YAG capsulotomy between contiguous States such as Utah and Nevada. Perhaps because of intersurgeon variation, time-specific estimates of rates of performing YAG vary widely. Furthermore, only one study adjusted for censoring and variable followup, so most rate estimates are crude at best (Javitt, Tielsch, Canner et al., 1992) (Table 8-2).

Table 8-3. Timing of YAG Capsulotomy After Cataract (more...)

Table 8-3. Timing of YAG Capsulotomy After Cataract Extraction (Months)

Source	Average Interval	Standard Deviation	Range
Coonan, Fung, Webster et al., 1985	24	NR	2-88
Ambler and Constable, 1988	24	NR	4-47
Chambless, 1985	NR	NR	1.5-114
Stern, Taylor, and Bernstein, 1985	24	NR	2-69
Knolle, 1985	25-36	NR	3-72
Flohr, Robin, and Kelley, 1985	26	17	3-106
Slomovic, Parrish, Forster et al., 1986	24	NR	2-360
Durham and Gills, 19851	24	NR	2-72
Aron-Rosa, 1985	NR	NR	7-420
Koch, Liu, Gill et al., 1989	27	NR	3-124
Gardner, Straatsma, and Pettit, 1985	13	NR	1-600
Brown, Thomas, Belcher et al., 1985	15	NR	3-36
Leff, Welch, and Tasman, 1987	15	NR	2-68
Capone, Rehkopf, Warnicki et al., 1990	23	NR	8-38
Javitt, Tielsch, Canner et al., 1992	12	08	0-24
Fourman and Apisson, 1991	17	12	NR
Liesegang, Bourne, and Ilstrup, 1985	34	NR	NR
Burratto, Ricci, and Vitali, 1985	17	NR	NR
Maltzman, Haupt, and Notis, 1989	24	NR	NR
Schubert, 1987	23	03	NR
Richter, Arzeno, Pappas et al., 1985a	12	03	NR
Lewis, Singer, Hanscom et al., 1987	13	NR	4-54

[1] Identical data reported in Shah, Gills, Durham et al., 1986.

Note: NR = Not reported.

In general, the need for YAG capsulotomy increases with increasing time after cataract surgery, with the larger studies reporting a crude incidence of 15-20 percent approximately 2 years after surgery (Table 8-3). The median and range of time from cataract surgery to YAG capsulotomy for the 22 studies that reported an average and/or range were 24 months and 1-600 months, respectively. Little information exists on the role of patient factors on the rate or timing of YAG capsulotomy.

Question 3: Is there evidence on indications, complications, and outcomes after YAG capsulotomy?

Fifty-seven studies address this question (Albert, Wade, Parrish et al., 1990; Ambler and Constable, 1988; Aron-Rosa, 1985; Axt, 1985; Bath and Fankhauser, 1986; Boen-Tan and Stilma, 1986; Brown, Stewart, Lynch et al., 1988; Brown, Thomas, Belcher et al., 1985; Burratto, Ricci, and Vitali, 1985; Canning, Capon, Sherrard et al., 1988; Capone, Rehkopf, Warnicki et al., 1990; Chambless, 1985; Channell and Bechman, 1984; Clorfeine and Parker, 1984; Corboy and Novak, 1989; Dardenne, Gerten, Kokkas et al., 1989; Deutsch and Goldberg, 1985; Durham and Gills, 1985 [identical data reported in Shah, Gills, Durham et al., 1986]; Ficker and Steele, 1985; Flohr, Robin, and Kelley, 1985; Fourman and Apisson, 1991; Gardner, Straatsma, and Pettit, 1985; Harris, Herman, and Fagadau, 1985; Javitt, Tielsch, Canner et al., 1992; Katzen, Fleischman, and Trokel, 1983; Knighton, Slomovic, and Parrish, 1985; Knolle, 1985; Koch, Liu, Gill et al., 1989; Kraff, Sanders, and Lieberman, 1985; Leff, Welch, and Tasman, 1987; Levy and Dodick, 1984; Levy and Pisacano, 1985; Lewis, Singer, Hanscom et al., 1987; Leys, Pameijer, and de Jong, 1985; Liesegang, Bourne, and Ilstrup, 1985; MacEwen and Baines, 1989; Maltzman, Haupt, and Cucci, 1989; Maltzman, Haupt, and Notis, 1989; Migliori, Beckman, and Channell, 1987; Milauskas, 1987; Nirankari and Richards, 1985; Ober, Wilkinson, Fiore et al., 1986; Peyman, Caldwell, Conway et al., 1985; Pollack, Brown, Crandall et al., 1989 [identical data reported in Pollack, Brown, Crandall et al., 1988]; Richter, Arzeno, Pappas et al., 1985a and 1985b; Rickman-Barger, Florine, Larson et al., 1989; Schubert, 1987; Shepherd, 1989b; Silverstone, Novack, Kelley et al., 1988; Slomovic and Parrish, 1985; Slomovic, Parrish, Forster et al., 1986; Stark, Worthen, Holladay et al., 1985; Steinert, Puliafito, Kumar et al., 1991; Stern, Taylor, and Bernstein, 1985; Stilma and Boen-Tan, 1986; Wasserman, Axt, and Sheets, 1985).

Most of the articles that included information on the indication for YAG capsulotomy made reference to some form of interference with the patient's ability to see well. In the two articles wherein this interference was quantified, the most prevalent measure used was best corrected visual acuity of 20/50 or worse in the presence of "significant" PCO (Maltzman, Haupt, and Cucci, 1989; Stern, Taylor, and Bernstein, 1985), whereas glare, light sensitivity, and/or hazy vision without decreased visual acuity were mentioned but not quantified in five papers (Chambless, 1985; Maltzman, Haupt, and Cucci, 1989; Maltzman, Haupt, and Notis, 1989; Milauskas, 1987; Shepherd, 1989b). Most articles either did not indicate the reason for YAG capsulotomy (n=13) or indicated that the reason for YAG capsulotomy was an opacified posterior capsule (n=6) or a clinical judgment (n=4).

Table 8-4. Complications of YAG Capsulotomy

Table 8-4. Complications of YAG Capsulotomy

Complication	Rate of Occurrence (Percent)
	Lowest	Highest
Increased glare	Rare	Rare
Retinal detachment	0	4.1
Cystoid macular edema	0	6.8
Endothelial cell loss	0	7
Uveitis	< 0.1	30
Corneal edema	1	2.4
Hyphema	1	9
Intraocular pressure elevation	2	95
Intraocular lens damage	4.4	95
Anterior vitreous rupture	6	41

Note: YAG = Yttrium aluminum garnet.

Source: Compiled from 57 reviewed articles and panel consensus.

Complications and outcomes of YAG capsulotomy were addressed in all of the 57 articles. Whereas the information on intraoperative and early postoperative complications is good in quality and comprehensive in scope, limited information exists on long-term complications. That which exists suffers from incomplete followup and uncertainties about the content and frequency of followup examinations. In addition, the literature showed that patient characteristics affect the incidence of complications. The rate of occurrence of complications following YAG capsulotomy is shown in Table 8-4.

The literature on outcomes and complications is discussed according to those articles that addressed elevated intraocular pressure (IOP) and retinal detachment and those that evaluated other outcomes and/or complications.

Elevated IOP: The most frequently studied complication of YAG capsulotomy is elevated IOP, with 37 articles included in this review (Aron-Rosa, 1985; Axt, 1985; Bath and Fankhauser, 1986; Boen-Tan and Stilma, 1986; Brown, Stewart, Lynch et al., 1988; Brown, Thomas, Belcher et al., 1985; Burratto, Ricci, and Vitali, 1985; Canning, Capon, Sherrard et al., 1988; Chambless, 1985; Channell and Bechman, 1984; Deutsch and Goldberg, 1985; Durham and Gills, 1985 [identical data reported in Shah, Gills, Durham et al., 1986]; Ficker and Steele, 1985; Flohr, Robin, and Kelley, 1985; Fourman and Apisson, 1991; Gardner, Straatsma, and Pettit, 1985; Harris, Herman, and Fagadau, 1985; Knolle, 1985; Kraff, Sanders, and Lieberman, 1985; Levy and Dodick, 1984; Levy and Pisacano, 1985; Leys, Pameijer, and de Jong, 1985; Liesegang, Bourne, and Ilstrup, 1985; Migliori, Beckman, and Channell, 1987; Nirankari and Richards, 1985; Peyman, Caldwell, Conway et al., 1985; Pollack, Brown, Crandall et al., 1989 [identical data reported in Pollack, Brown, Crandall et al., 1988]; Richter, Arzeno, Pappas et al., 1985a and 1985b; Schubert, 1987; Silverstone, Novack, Kelley et al., 1988; Slomovic and Parrish, 1985; Stark, Worthen, Holladay et al., 1985; Steinert, Puliafito, Kumar et al., 1991; Stern, Taylor, and Bernstein, 1985; Stilma and Boen-Tan, 1986; Wasserman, Axt, and Sheets, 1985).

Since definitions vary widely on what is considered "elevated IOP" and since even in the early postoperative period the timing of IOP measurement varied considerably, the IOP data are difficult to evaluate. The studies indicate that IOP may be elevated significantly during the first 24-48 hours after YAG capsulotomy. A report on one series of 66 patients (Slomovic and Parrish, 1985) that defined increased IOP as at least 5 mmHg over pre-YAG IOP showed a frequency of 53 percent at 1 hour, 65 percent at 2 hours, 61 percent at 3 hours, 55 percent at 4 hours, and 20 percent at 24 hours. The degree to which these elevations persist in patients is a topic of current study, and a recent article (Steinert, Puliafito, Kumar et al., 1991) reported an incidence of 1.3 percent new glaucoma or worsened preexisting glaucoma in 897 eyes that had undergone YAG capsulotomy. Most articles, however, report that early postoperative IOP elevations were responsive to treatment. Late onset (occurring 6 months or more after YAG capsulotomy) of elevated IOP was noted in 5.9 percent of 237 eyes that had undergone extracapsular cataract extraction (ECCE) with later YAG capsulotomy (Fourman and Apisson, 1991).

Retinal Detachment: Information on retinal detachment after YAG capsulotomy was reported in 16 articles (Ambler and Constable, 1988; Axt, 1985; Bath and Fankhauser, 1986; Chambless, 1985; Dardenne, Gerten, Kokkas et al., 1989; Durham and Gills, 1985; Harris, Herman, and Fagadau, 1985; Javitt, Tielsch, Canner et al., 1992; Knolle, 1985; Koch, Liu, Gill et al., 1989; Leff, Welch, and Tasman, 1987; MacEwen and Baines, 1989; Ober, Wilkinson, Fiore et al., 1986; Rickman-Barger, Florine, Larson et al., 1989; Stark, Worthen, Holladay et al., 1985; Steinert, Puliafito, Kumar et al., 1991). Except for the study by Javitt et al. (Javitt, Tielsch, Canner et al., 1992), no articles accounted for variable followup and censoring in the analysis, resulting in incidence estimates that are crude at best. Those studies that followed series of YAG patients reported a crude retinal detachment incidence ranging from 0 to 4.1 percent, whereas the 36-month post-ECCE probability of retinal detachment in patients who required YAG capsulotomy was 1.8 percent (Javitt, Tielsch, Canner et al., 1992). For this occurrence, five articles (Dardenne, Gerten, Kokkas et al., 1989; Javitt, Tielsch, Canner et al., 1992; Leff, Welch, and Tasman, 1987; MacEwen and Baines, 1989; Rickman-Barger, Florine, Larson et al., 1989) evaluated risk factors, including high myopia, younger age, male sex, lattice degeneration, and a history of retinal detachment in the fellow eye. However, estimates of relative risk are available only in the study by Javitt et al. (Javitt, Tielsch, Canner et al., 1992), which could not address clinical variables not present in the Medicare data base. In that study, patients who underwent YAG capsulotomy had a 3.9-fold increase in retinal detachment risk when compared with ECCE patients who did not undergo this procedure. This risk was independent of other significant factors that increased the post-ECCE risk of retinal detachment, including younger age, male sex, and white race.

Other Outcomes and/or Complications: Other outcomes and complications included improved visual acuity, opening of the posterior capsule, improved glare threshold, uveitis, intraocular lens (IOL) damage, cystoid macular edema, vitreous prolapse, endothelial cell loss, hyphema, and pupillary block. Visual acuity improvement was noted in 22 articles (Albert, Wade, Parrish et al., 1990; Axt, 1985; Bath and Fankhauser, 1986; Burratto, Ricci, and Vitali, 1985; Capone, Rehkopf, Warnicki et al., 1990; Chambless, 1985; Deutsch and Goldberg, 1985; Durham and Gills, 1985; Flohr, Robin, and Kelley, 1985; Gardner, Straatsma, and Pettit, 1985; Harris, Herman, and Fagadau, 1985; Katzen, Fleischman, and Trokel, 1983; Knighton, Slomovic, and Parrish, 1985; Knolle, 1985; Levy and Dodick, 1984; Levy and Pisacano, 1985; Nirankari and Richards, 1985; Peyman, Caldwell, Conway et al., 1985; Stark, Worthen, Holladay et al., 1985; Steinert, Puliafito, Kumar et al., 1991; Stern, Taylor, and Bernstein, 1985; Wasserman, Axt, and Sheets, 1985), and improvement was observed in 65-100 percent of those undergoing YAG capsulotomy. However, variation in followup after YAG capsulotomy was considerable, and losses to followup were often substantial. Reporting of both pre- and post-YAG visual acuity was often lacking, and when present, often categorical rather than patient specific. Capsular opening was specified in four papers and ranged from 97 to 100 percent (Capone, Rehkopf, Warnicki et al., 1990; Gardner, Straatsma, and Pettit, 1985; Lewis, Singer, Hanscom et al., 1987; Stark, Worthen, Holladay et al., 1985). An increase in the glare threshold after YAG capsulotomy was noted in two articles (Capone, Rehkopf, Warnicki et al., 1990; Knighton, Slomovic, and Parrish, 1985).

Other than IOP elevation, the most commonly reported complication was damage to the patient's IOL, which was reported in 20 unique articles with a frequency ranging from 4.4 to 95 percent (Aron-Rosa, 1985; Axt, 1985; Bath and Fankhauser, 1986; Burratto, Ricci, and Vitali, 1985; Chambless, 1985; Corboy and Novak, 1989; Deutsch and Goldberg, 1985; Durham and Gills, 1985 [identical data reported in Shah, Gills, Durham et al., 1986]; Flohr, Robin, and Kelley, 1985; Gardner, Straatsma, and Pettit, 1985; Harris, Herman, and Fagadau, 1985; Levy and Dodick, 1984; Levy and Pisacano, 1985; Lewis, Singer, Hanscom et al., 1987; Liesegang, Bourne, and Ilstrup, 1985; Nirankari and Richards, 1985; Peyman, Caldwell, Conway et al., 1985; Stark, Worthen, Holladay et al., 1985; Stern, Taylor, and Bernstein, 1985; Wasserman, Axt, and Sheets, 1985). The damage usually took the form of minor surface pitting. Two articles (Gardner, Straatsma, and Pettit, 1985; Nirankari and Richards, 1985) reported lost vision in two patients due to the IOL damage. Rupture of the anterior vitreous face was noted in eight papers (Bath and Fankhauser, 1986; Ficker and Steele, 1985; Harris, Herman, and Fagadau, 1985; Koch, Liu, Gill et al., 1989; Lewis, Singer, Hanscom et al., 1987; Nirankari and Richards, 1985; Schubert, 1987; Stark, Worthen, Holladay et al., 1985), with a frequency ranging from 6 to 41 percent of eyes.

Ten unique articles (Albert, Wade, Parrish et al., 1990; Axt, 1985; Bath and Fankhauser, 1986; Chambless, 1985; Durham and Gills, 1985 [identical data reported in Shah, Gills, Durham et al., 1986]; Harris, Herman, and Fagadau, 1985; Knolle, 1985; Levy and Pisacano, 1985; Lewis, Singer, Hanscom et al., 1987; Steinert, Puliafito, Kumar et al., 1991) evaluated the post-YAG frequency of cystoid macular edema, but because of the unavailability of pre-YAG angiographic documentation in all but one article (Albert, Wade, Parrish et al., 1990), the postoperative rates of cystoid macular edema (which ranged from 0 to 6.8 percent) cannot be interpreted as incidence estimates.

Eleven articles (Axt, 1985; Burratto, Ricci, and Vitali, 1985; Chambless, 1985; Gardner, Straatsma, and Pettit, 1985; Harris, Herman, and Fagadau, 1985; Levy and Dodick, 1984; Levy and Pisacano, 1985; Lewis, Singer, Hanscom et al., 1987; Peyman, Caldwell, Conway et al., 1985; Stark, Worthen, Holladay et al., 1985; Wasserman, Axt, and Sheets, 1985) reported on post-YAG uveitis, which was usually mild and was found in 1-30 percent of examined eyes at variable post-YAG time periods. The definition of uveitis was not standardized. Corneal endothelial cell loss was reported in five articles (Axt, 1985; Kraff, Sanders, and Lieberman, 1985; Liesegang, Bourne, and Ilstrup, 1985; Slomovic, Parrish, Forster et al., 1986; Wasserman, Axt, and Sheets, 1985) and ranged from 0 to 7 percent. Mild transitory corneal edema ranging from 1 to 2.4 percent was reported in three articles (Levy and Dodick, 1984; Levy and Pisacano, 1985; Liesegang, Bourne, and Ilstrup, 1985), and iris bleeding with hyphema ranging from 1 to 2.4 percent was noted in seven papers (Bath and Fankhauser, 1986; Deutsch and Goldberg, 1985; Flohr, Robin, and Kelley, 1985; Gardner, Straatsma, and Pettit, 1985; Harris, Herman, and Fagadau, 1985; Levy and Pisacano, 1985; Nirankari and Richards, 1985). The association of preoperative ocular, systemic, or demographic factors with the risk of YAG-related complications received little attention in this literature.

The quality of information in the large number of articles that describe intraoperative and early postoperative complications and visual acuity results is quite good (see Table 8-4). However, the manner in which data are presented on the IOP rise during the first 24-48 hours varies somewhat. The accuracy and comparability of estimated rates of longer term complications and outcomes are affected by incomplete followup and uncertainties regarding the frequency and content of followup examinations. Only one (Javitt, Tielsch, Canner et al., 1992) of the studies of retinal detachment after YAG capsulotomy adjusted for variable followup, so the estimates are affected by this factor. Definitions of some outcomes (e.g., uveitis) are not standardized, and postoperative incidence estimates of cystoid macular edema are suspect in those studies that lack complete pre-YAG angiography. Patient characteristics may affect the incidence of complications.

Diagnosis

The diagnosis of functional impairment due to PCO is made in the context of a patient who had previously undergone cataract surgery and who now has an opacified posterior capsule. The same general approach as that outlined for cataract should be followed. However, the patients who have PCO differ from those with cataract in an important way. Generally, PCO develops more rapidly than cataract. Thus, the patient with PCO has enjoyed improved vision in the more recent past. Therefore, in this context, diagnosis involves a consideration of the following:

• The degree of functional impairment.

• The amount of PCO.

• Other possible causes of decreased vision following cataract surgery.

Indications for Surgery

Laser capsulotomy is appropriate and justified when the following subjective, objective, and educational criteria are met, as outlined in Indications for Surgery in Chapter 5.

• Subjective: The ability to carry out needed or desired activities is impaired.

• Objective: The eye examination confirms the diagnosis of PCO and excludes other ocular causes of functional impairment.

• Educational: The patient has been educated about the risks and benefits of laser surgery to the posterior capsule.

The patient determines if the expected improvements in the disability outweigh the risks and costs of laser surgery.

Occasionally, laser capsulotomy is indicated for reasons other than improving functional disability -- to provide a better visualization of the posterior pole to diagnose and treat retinal detachment, macular disease, and diabetic retinopathy; to evaluate the optic nerve head; and to diagnose posterior pole tumors or other conditions requiring ophthalmologic evaluation.

Contraindications

Preoperative Ophthalmic Evaluation

The panel did not evaluate the use of tests of contrast sensitivity, glare, and potential vision in the management of PCO. Fluorescein angiography may be indicated when there is clinical evidence of macular disease and/or the degree of capsular opacity appears insufficient to account for the level of decreased visual acuity. This should be documented in the chart. B-scan ultrasonography is indicated when the degree of capsular opacification is of a severity that the posterior pole cannot be visualized and when the degree of central visual loss is severe and seemingly unexplained by the degree of opacification. The preoperative ophthalmic evaluation should include a history and complete ocular examination.

Preoperative Medical Evaluation

YAG capsulotomy is a surgical procedure that is performed without the need for regional anesthesia other than an application of topical anesthetic to the cornea. However, vasoactive drugs (e.g., aproclonidine and beta-adrenergic blocking agents) are commonly used in the perioperative period. The panel concurs that it is the responsibility of the ophthalmologist who will perform the laser surgery to assess the medical suitability of the patient for the procedure and the use of these agents in the perioperative phase.

Surgical Technique

Laser surgery of the posterior capsule is performed in the office, ambulatory surgical center, or a hospital outpatient department, under biomicroscopic magnification. A contact lens may be used to enhance visualization of the posterior capsule and help stabilize the eye during the procedure. The literature search did not address technical aspects of the surgical procedure. However, the panel concurred that careful consideration should be given to the amount of energy used, the size of the opening, and its location, since these may influence the subsequent risk of complications.

Complications

The major complications of YAG laser capsulotomy include elevated IOP, retinal detachment, cystoid macular edema, damage to the IOL, hyphema, dislocation of the IOL, and corneal edema.

Postoperative Care

The ophthalmologist who performed the laser capsulotomy has an ethical and legal responsibility to provide postoperative care to the patient. The postoperative period is considered to extend 2 weeks from the end of the procedure. If complications develop (e.g., persistent elevated IOP, retinal detachment, cystoid macular edema, or corneal abrasion), the ophthalmologist has the obligation to provide appropriate care or, with the patient's consent, to refer to another ophthalmologist.

Benefits and Harms of YAG Capsulotomy

As in the case of cataract surgery, there are no data that precisely define the risk and benefits of YAG capsulotomy. However, some estimates can be made based on literature reports of outcomes and complications.

Harms: Negative Outcomes.

Table 8-5. Estimated Rate of Negative Outcomes of YAG (more...)

Table 8-5. Estimated Rate of Negative Outcomes of YAG Capsulotomy

>= 1:100	< 1:100	< 1:10,000	< 1:100,000
Glaucoma	Retinal detachment	Double vision	Loss of eye
Failure to improve	Problems with glare	Dislocated lens	Chronic pain
Increased need for medication	Cystoid macular edema	Disorientation	Depression
Adverse effects from the drugs used in treatment	Need for further surgery	Clinically significant damage to intraocular lens	Psychosis
	Loss of permanent vision		Suicide

Note: Except for failure to improve, disorientation, and clinically significant damage to intraocular lens, the rate increases when there are comorbid conditions. The rate < 1:1,000 is not applicable to this table. YAG = Yttrium aluminum garnet.

Source: Compiled from reviewed literature and panel consensus.

Harms that may occur as a result of YAG capsulotomy may be defined as negative outcomes. These include failure to achieve expected positive outcomes or failure to relieve or improve the preoperative functional impairment as perceived by the patient, the patient's family, or the ophthalmologist who performed the YAG capsulotomy. In addition, negative outcomes refer to the development of complications that either impair the patients' visual function or consume their resources Table 8-5. It should be noted that these complication rates are based on data obtained from the literature review and the consensus of the panel. Therefore, they should be considered only estimates.

The success rate of YAG capsulotomy is reduced in the presence of comorbid ocular conditions. Again, data are lacking to give precise estimates of this effect, but outcome is influenced by conditions such as corneal disease leading to loss of corneal clarity, preexisting glaucoma, and preexisting retinal disorders such as retinal detachment disease, macular degeneration, and diabetic retinopathy. Each contributes to a loss of vision and, therefore, to a loss of the effect of the YAG capsulotomy. This may be immediate (that is, proximal to the time of surgical effect) or may be manifested a considerable time after the YAG capsulotomy is complete.

In considering all possible benefits and harms, these conditions must be taken into account. The degree to which they are treated or will be treated will influence the outcome. Overall, in the presence of these conditions, the success rate of the YAG capsulotomy is reduced compared with the overall high level of the expected outcome in the eye without these comorbid conditions.

Agency for Health Care Policy and Research

• Jean R. Slutsky, PA, MSPH

• Lawrence E. Williams

• Margaret K. Rutherford

• Rose Calbert Findley, MUP

• Harriett V. Bennett

National Library of Medicine

• Ione Auston, MLS

Contract Agencies

• Health Systems Research, Inc.

• Washington, D.C.

• Mikalix and Company, Inc.

• Waltham, Massachusetts

• Moshman Associates, Inc.

• Bethesda, Maryland

• Washington Consulting Group, Inc.

• Washington, D.C.

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