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

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.

Prevalence and risk factors for hypertension and association with ethnicity in Nigeria: results from a national survey.

OBJECTIVE: Non-communicable diseases are now a global priority. We report on the prevalence of hypertension and its risk factors, including ethnicity, in a nationally representative sample of Nigerian adults recruited to a survey of visual impairment. METHODS: multi-stage, stratified, cluster random sample with probability proportional to size procedures was used to obtain a nationally representative sample of 13 591 subjects aged ≥ 40 years. Of these, 13 504 (99.4%) had a blood pressure measurement. RESULTS: The prevalence of hypertension was 44.9% [95% confidence interval (CI): 43.5-46.3% ]. Increasing age, gender, urban residence and body mass index were independent risk factors (p < 0.001). The Kanuri ethnic group had the highest prevalence of hypertension (77.5%, 95% CI: 71.0-84.0%). CONCLUSIONS: The high prevalence of hypertension in Nigeria is a cause for concern and suggests that it is inevitable that the impact of hypertension-related ill health is imminent, with the accompanying financial and societal costs to families and the state of Nigeria.

Coverage of hospital-based cataract surgery and barriers to the uptake of surgery among cataract blind persons in nigeria: the Nigeria National Blindness and Visual Impairment Survey.

PURPOSE: To determine cataract surgical coverage, and barriers to modern cataract surgery in Nigeria. METHODS: Multistage stratified cluster random sampling was used to identify a nationally representative sample of 15,027 persons aged 40+ years. All underwent visual acuity testing, frequency doubling technology visual field testing, autorefraction, and measurement of best corrected vision if <6/12 in one or both eyes. An ophthalmologist examined the anterior segment and fundus through an undilated pupil for all participants. Participants were examined by a second ophthalmologist using a slit lamp and dilated fundus examination using a 90 diopter condensing lens if vision was <6/12 in one or both eyes, there were optic disc changes suggestive of glaucoma, and 1 in 7 participants regardless of findings. All those who had undergone cataract surgery were asked where and when this had taken place. Individuals who were severely visually impaired or blind from unoperated cataract were asked to explain why they had not undergone surgery. RESULTS: A total of 13,591 participants were examined (response rate 89.9%). Prevalence of cataract surgery was 1.6% (95% confidence interval 1.4-1.8), significantly higher among those aged ≥70 years. Cataract surgical coverage (persons) in Nigeria was 38.3%. Coverage was 1.7 times higher among males than females. Coverage was only 9.1% among women in the South-South geopolitical zone. Over one third of those who were cataract blind said they could not afford surgery (36%). CONCLUSIONS: Cataract surgical coverage in Nigeria was among the lowest in the world. Urgent initiatives are necessary to improve surgical output and access to surgery.