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Quiñones A, Gleitsmann K, Freeman M, et al. Benefits and Harms of Femtosecond Laser Assisted Cataract Surgery: A Systematic Review [Internet]. Washington (DC): Department of Veterans Affairs (US); 2013 Dec.


Question 1: Are the objectives, scope and methods for this review clearly described?
1Yes. I think the objectives were well spelled out. We did not ask specifically for any cost/benefit analysis so was done nicely.Noted, thank you.
3Yes. (No comment)Noted.
4Yes. (No comment)Noted.
5Yes. The objectives could be more clearly stated as the purpose of this work is to systematically review and critically appraise the available evidence of FSL assisted cataract surgery vs conventional surgery.We thank the reviewer for the comment. The reviewer is correct that one aspect of the review is to appraise available evidence of FSL compared to conventional cataract surgery. However, the harms and learning curve assessment questions were not limited to comparative studies. We have clarified the objectives of the report in the background and methods sections.
2. Is there any indication of bias in our synthesis of the evidence?
1No. I did not see any, but the papers reviewed certainly had bias as you pointed out.Noted, thank you.
3No. (No comment)Noted.
4No. (No comment)Noted.
5No. (No comment)Noted.
3. Are there any published or unpublished studies that we may have overlooked?
1No. None that I am aware of.Noted.
3No. (No comment)Noted.
4No. Given the technology is fairly new as far as FDA approval, high level evidence literature is limited.Noted.
5Yes. Methods: The recommended databases to search (as a minimum) by the Cochrane Collaboration is EMBASE, MEDLINE, and CENTRAL. I suggest reviewing EMBASE and CENTRAL in addition to all the other sources searched.We have clarified the databases searched in Figure 2 (literature flow) of the report. Our search of the Cochrane library included the CENTRAL register of controlled trials. Unfortunately, our library does not subscribe to EMBASE so we do not have access to that database. However, we are reasonably confident that we have captured the relevant literature for the topic, given that we have searched the grey literature and recent conference proceedings in this quickly evolving field.
4. Please write additional suggestions or comments below. If applicable, please indicate the page and line numbers from the draft report.
1Were any of the papers quoted funded directly by manufacturers? It seems like even in the papers quoted you had methodological questions, for instance were patients used in multiple reports and that most of the “better” papers were all done by one surgeon, so the question of learning curve remains?We examined the acknowledgements listed for each of the papers and could only report on the consulting fees and honoraria received by study authors. In addition, there were very few papers examining the issue of learning curve. As a result, the evidence available to answer key question 3 is very sparse.
2.I appreciate the amount of effort the coordinators have made for this systematic review. I have the following comments. A limitation of meta-analysis restricted to methodologically sound comparison studies is failure to capture relatively infrequent but important adverse outcomes that begin to be reported as individual or small series reports several years after institution of a new technology. This pattern was seen in corneal refractive surgery after institution of LASIK (laser in situ keratomileusis). Case reports of ischemic optic neuropathy (anterior or posterior) with partial loss of vision were linked to the high intraocular pressures from the metal suction rings used for the standard microkeratome procedure (references 1-3). A similar case of optic neuropathy has been reported with a femtosecond laser using a low-pressure suction ring (reference 4). As a LASIK surgeon, I am aware of other unreported cases. As you note in your review, all docking devices currently used in femtosecond platforms lead to an increase in intraocular pressure, which puts the microcirculation of the optic nerve at risk, especially in patients with microvascular disease from diabetes or hypertension. This effect may be especially important in the VHA population. Ischemic optic neuropathy has also been reported after uncomplicated conventional phacoemulsification (References 5-7).
  1. Lee AG, et al. Optic neuropathy associated with laser in situ keratomileusis. J Cataract Refract Surg 2000;11:1581-4.
  2. Bushley DM, et al. Visual field defect associated with laser in situ keratomileusis. Am J Ophthalmol 2000;129:668-71.
  3. Cameron BD, et al. Laser in situ keratomileusis-induced optic neuropathy. Ophthalmology 2001;108:660-5.
  4. Maden A, et al. Nonarteritic ischemic optic neuropathy after LASIK with femtosecond laser flap creation. J Neuro-Ophthalmol 2008;28:242-3.
  5. Lee H, et al. A case of decreased visual field after uneventful cataract surgery; nonarteritic anterior ischemic optic neuropathy. Korean J Ophthalmol 2010;24:57-61.
  6. Luscavage LE, et al. Posterior ischemic optic neuropathy after uncomplicated cataract extraction. Am J Ophthalmol 2001;132:408-9.
  7. McCulley TJ, et al. Incidence of nonarteritic anterior ischemic optic neuropathy associated with cataract extraction. Ophthalmology 2001;108:1275-8
We thank the reviewer for the insightful comments. In an attempt to identify all of the adverse events associated with FLACS, we included various study designs, even those of case reports. As the reviewer points out, these low prevalence events are not appropriate for meta-analysis. As noted in our review, all of the FSL platforms have been associated with some elevation of IOP during the procedure. This has not been noted to be as severe as the amaurosis-inducing levels common with LASIK procedures, which generate high IOPs with the use of microkeratomes. Our report does reflect the concern with even mild elevations of IOP being potentially harmful to glaucoma patients and may therefore exclude Veterans with this common comorbidity from being candidates for FLACS.
2.You mention disposable costs for FLACS of $150-300. What are the disposable costs for conventional phaco?Our review has been amended to reflect this cost issue. The disposable costs of FLACS and conventional phacoemulsification surgery are comparable (both involve irrigation/ aspiration and phacoemulsification procedures). The additional incremental cost of FLACS is the $150-300 per patient charge for the sterile, single-use patient interface device.
3The draft report addresses on point the request for information.Noted.
4The review covers as one of its key questions “What is the evidence that the experience of the surgeon is associated with adverse effects of FLACS?” a couple studies showed less adverse events with more experience with FLACS. It would be nice to compare the surgical learning curve of FLACS vs Conventional cataract. There is some early literature in presentation and poster on this…not sure publications exists. This will be key for the VA given it is very involved in resident cataract surgery teaching.
Prickett, 201340
Initial Resident Experience Performing Cataract Surgery with and without Femtosecond Laser (Conference proceeding)
ARVO Poster Session, 2013
Thank you for the comment. However, the comparative learning curve of FLACS versus conventional surgery is outside of the scope of the review. This will be important in future questions of learning curve comparing surgical procedures (conventional compared to FLACS)
5Although meta-analyses of observational studies are not as frequent as for RCTs, there are guidelines (MOOSE) that are accepted to estimate summary effects based on observational studies. Nonetheless, if the authors consider that the quality of the observational studies (e.g., bias) preclude a meta-analysis, then is ok not to do it.We thank the reviewer for the comment, and agree that the concerns with the included observational studies preclude meta-analyses of additional outcomes.
Optional Dissemination and Implementation Questions
5. Are there any VA clinical performance measures, programs, quality improvement measures, patient care services, or conferences that will be directly affected by this report? If so, please provide detail.
1None that I am aware of. I have heard of several more machines being requested and some purchased across the VA system.Noted.
3The report supports the FDA approval of this technologyNoted.
4No. (No comment)Noted.
6. Please provide any recommendations on how this report can be revised to more directly address or assist implementation needs.
1None. The way I interpreted your results was that there was weak to moderate support of some advantages to this technology but the same for the adverse effects. Even this information is generated from reports that have either stated or possible conflict of interest. While not in your prevue, I am hoping this report can be submitted with any application for technology across the VISN.Noted, thank you for your comment.
3No recommendationNoted.
4No. (No comment)
5In methodology there are some issues that should be addresed:
How heterogeneity was assessed and examined (stratification, regression)?, how bias was evaluated?, which effect measure was used for meta-analysis and which weighting method (random, fixed models)? Also, it should be stated that STATA was used for statistical analysis.
We have provided more information in the methodological details of the meta-analyses. All analyses were conducted in StataIC 11, and we assessed the presence of statistical heterogeneity among the studies by using standard chi-square tests, and the magnitude of heterogeneity by using the I2 statistic. We explored models using both mean and ratio of means (SoM) based on a random effects model (combining means used the DL method and combining SoM used the PL method) – however, we do not report the combined estimates due to too much heterogeneity and rely on the forest plots as a visual aid for readers.
Image resultsf1
Cover of Benefits and Harms of Femtosecond Laser Assisted Cataract Surgery: A Systematic Review
Benefits and Harms of Femtosecond Laser Assisted Cataract Surgery: A Systematic Review [Internet].
Quiñones A, Gleitsmann K, Freeman M, et al.
Washington (DC): Department of Veterans Affairs (US); 2013 Dec.

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