title: Prevalence of refractive errors in a rural South Indian population.
abstract: OBJECTIVE
  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.
authors.affiliation: Glaucoma Project, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Prema
authors.initials: P
authors.lastname: Raju
authors.forename: S Ve
authors.initials: SV
authors.lastname: Ramesh
authors.forename: Hemamalini
authors.initials: H
authors.lastname: Arvind
authors.forename: Ronnie
authors.initials: R
authors.lastname: George
authors.forename: Mani
authors.initials: M
authors.lastname: Baskaran
authors.forename: Pradeep G
authors.initials: PG
authors.lastname: Paul
authors.forename: Govindasamy
authors.initials: G
authors.lastname: Kumaramanickavel
authors.forename: Catherine
authors.initials: C
authors.lastname: McCarty
authors.forename: Lingam
authors.initials: L
authors.lastname: Vijaya
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001251:Astigmatism / Q000453:epidemiology / Q000503:physiopathology; D003710:Demography; D048909:Diabetes Complications; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology / Q000209:etiology; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000453:epidemiology / Q000503:physiopathology; D015995:Prevalence; D012030:Refractive Errors / Q000453:epidemiology*; D012424:Rural Population / Q000706:statistics & numerical data; D017678:Sex Distribution