Prevalence of refractive errors in a rural south Indian population

Purpose. To report the prevalence of refractive errors in a rural south Indian population. Methods. Four thousand eight hundred subjects (age, >39 years) from rural south India were enumerated for a population-based study. All participants underwent complete ophthalmic evaluation. Subjects who were phakic in the right eye with best corrected visual acuity of 20/40 or better were included for analysis. Association of refractive errors with age, sex, cataract, and diabetes mellitus were analyzed. Results. Of the 3924 responders, 2508 were eligible. The unadjusted prevalence of emmetropia (spherical equivalent [SE], -0.50 to +0.50 diopter sphere [DS]), myopia (SE<-0.50 DS), high myopia (SE<-5.00 DS), and hyperopia (SE>0.50 DS) were 50.60%, 26.99%, 3.71%, and 18.70% and age and gender adjusted for the rural Tamil Nadu population were 46.77%, 30.97%, 4.32%, and 17.94%, respectively. The prevalence of emmetropia decreased significantly with age (P<0.0001), and the prevalence of myopia and high myopia increased significantly with age (P<0.001) and were significantly associated with nuclear sclerosis (P<0.001). The prevalence of hyperopia increased until 60 years of age and then decreased. Hyperopia was more common among women than men (P<0.001) and was negatively associated with nuclear sclerosis (P<0.001) and positively with diabetes mellitus (P=0.008). Of the participants with astigmatism (cylindrical error greater than 0.50 DC), 9.80% had with-the-rule (WTR) and 77.44% against-the-rule (ATR) astigmatism. The prevalence of WTR and ATR astigmatism significantly decreased (P<0.001) and increased (P=0.006) with age, respectively. Conclusions. The pattern of refractive errors in this rural south Indian population is similar to those reported in other tropical regions of the world.