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Ophthalmology. 2011 Apr;118(4):719-24. doi: 10.1016/j.ophtha.2010.08.025. Epub 2010 Nov 4.

Outcome of cataract surgery in Nigeria: visual acuity, autorefraction, and optimal intraocular lens powers--results from the Nigeria national survey.

Author information

1
Ministry of Health Minna, Niger State, Nigeria.

Abstract

OBJECTIVE:

To describe presenting and corrected visual acuities after cataract surgery in a nationally representative sample of adults. Another objective was to describe refractive errors in operated eyes and to determine the optimal range of intraocular lens (IOL) powers for this population.

DESIGN:

Cross-sectional, population-based survey.

PARTICIPANTS:

Adults aged 40 years and more were selected using multistage stratified sampling and proportional to size procedures. A sample size of 15027 was calculated, and clusters were selected from all states.

METHODS:

Individuals who had undergone cataract surgery were identified from interview and examination. All had their presenting visual acuity (VA) measured using a reduced logarithm of the minimum angle of resolution chart and underwent autorefraction. Corrected VAs were assessed using the autorefraction results in a trial set. An ophthalmologist conducted all examinations, including slit-lamp and dilated fundus examination. Causes of visual loss were determined for all eyes with a presenting VA <6/12 using the World Health Organization recommendations. Biometry data were derived from 20449 phakic eyes using the SRK-T formula after excluding those with poor VA or corneal opacities.

MAIN OUTCOME MEASURES:

Presenting and corrected visual acuities in pseudo/aphakic individuals and autorefraction findings; biometry profile of Nigerian adults.

RESULTS:

Data from 288 eyes of 217 participants were analyzed. Only 39.5% of eyes had undergone IOL implantation at surgery. Only 29.9% of eyes had a good outcome (i.e., ≥6/18) at presentation, increasing to 55.9% with correction. Use of an IOL was the only factor associated with a good outcome at presentation (odds ratio 9.0; 95% confidence interval, 4.3-18.9; P=0.001). Eyes undergoing cataract surgery had a higher prevalence and degree of astigmatism than phakic eyes. Biometry data reveal that posterior chamber IOL powers of 20, 21, and 22 diopters (D) (A constant 118.0) will give a postoperative refraction range of -2.0 D to emmetropia in 71.4% of eyes, which increases to 82.6% if 19 D is also included.

CONCLUSIONS:

Postoperative astigmatism needs to be reduced through better surgical techniques and training, and use of biometry should be standard of care.

PMID:
21055820
DOI:
10.1016/j.ophtha.2010.08.025
[Indexed for MEDLINE]

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