Prevalence of and risk factors for age-related macular degeneration in Nepal: the Bhaktapur Retina Study

Raba Thapa,1 Sanyam Bajimaya,1 Govinda Paudyal,1 Shankar Khanal,2 Stevie Tan,3 Suman S Thapa,1 Ger van Rens3 1Vitreo-retina Service, Tilganga Institute of Ophthalmology, Kathmandu, 2Central Departments of Statistics, Tribhuvan University, Kirtipur, Nepal; 3Department of Ophthalmology, Vrije University Medical Center, Amsterdam, the Netherlands Aim: This study aimed to explore the prevalence of and risk factors for age-related macular degeneration (AMD) in an elderly population in Nepal. Subjects and methods: This is a population-based, cross-sectional study. A sample size of 2,100 was calculated. A total of 1,860 (88.6%) subjects aged >60 years were enrolled for the study from 30 clusters in the district. Detailed history, visual acuity, and anterior segment and posterior segment examinations were performed. AMD was graded according to the International ARM Epidemiological Study Group. Results: Among the total study population, 659 subjects had any AMD (35.43%; 95% confidence interval [CI]: 33.25–37.65), 484 had mild dry AMD (26.02%; 95% CI: 24.04–28.08), 143 had intermediate dry AMD (7.69%; 95% CI: 6.52–8.99), 19 had geographic atrophy (1.02%; 95% CI: 0.61–1.59), and 13 had wet AMD (0.70%; 95% CI: 0.37–1.19). The overall prevalence of early and late AMD was 33.71% and 1.72%, respectively. Among subjects with dry and wet AMD, 36.53% and 46.1% had visual impairment, while 2.78% and 23.08% were blind, respectively. In multivariate analysis, AMD was significantly higher in subjects with an increased number of cigarettes smoked per day (odds ratio [OR] 1.02, 95% CI: 1.01–1.04; P=0.007) and in subjects with pseudophakia (OR 1.45, 95% CI: 1.12–1.87; P=0.005). Conclusion: One-third of the population aged ≥60 years have some form of AMD. There was a significant association with the number of cigarettes consumed and with previous cataract surgery. Keywords: age-related macular degeneration, prevalence, risk factors, Nepal