Planning low vision services in India: a population-based perspective

Abstract

Objective: To assess the prevalence and causes of low vision in a population in southern India for planning low vision services. Design: Population-based, cross-sectional study. Participants: A total of 10,293 persons of all ages from 94 clusters representative of the population of the Indian state of Andhra Pradesh. Methods: The participants underwent a detailed eye examination, including measurement of visual acuity with logarithm of the minimum angle of resolution charts, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, and stereoscopic dilated fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were done when indicated using predefined criteria. Main outcome measures: Low vision was defined as permanent visual impairment that was not correctable with refractive error correction or surgical intervention. The participants with best-corrected distance visual acuity <6/18 to perception of light or central visual field <10° because of an untreatable cause in both eyes were considered as having low vision. Results: Low vision was present in 144 participants, an age, gender, and urban-rural distribution adjusted prevalence of 1.05% (95% confidence interval, 0.82%-1.28%). The most frequent causes of low vision included retinal diseases (35.2%), amblyopia (25.7%), optic atrophy (14.3%), glaucoma (11.4%), and corneal diseases (8.6%). Multivariate analysis showed that the prevalence of low vision was significantly higher with increasing age, and there was a trend for higher prevalence with decreasing socioeconomic status. Extrapolating these data to the estimated 1014 million population of India in the year 2000, 10.6 (95% confidence interval, 8.4-12.8) million people would have low vision. Conclusions: These data imply that there is a significant burden of low vision in this population, suggesting the need for low vision services.