title: Comparison of refractive errors and factors associated with spectacle use in a rural and urban South Indian population.
abstract: OBJECTIVE
  To compare the prevalence of refractive errors and factors associated with spectacle use in a rural and urban south Indian population.
  
  
  METHODS
  Four thousand eight hundred subjects (age> 39 years) each from rural and urban Tamil Nadu were enumerated for a population-based study. All participants underwent a complete ophthalmic evaluation including best-corrected visual acuity (BCVA), objective and subjective refraction. Out of 3924 rural responders 63.91% and out of 3850 urban responders 81.64% were phakic in the right eye with BCVA of 20/40 or better and were included in the study. Association of spectacle use and refractive errors with different parameters were analysed using logistic regression.
  
  
  METHODS
  Chi square, t test, Chi square for trend and Pearson's correlation coefficient were used for analysis.
  
  
  RESULTS
  Spectacle use was significantly higher and positively associated with literacy and employment in the urban population. The age and gender-adjusted prevalence of emmetropia, myopia of spherical equivalent (SE) < or =-0.50 diopter sphere (DS), high myopia (SE < or =-5.00DS), hyperopia (SE> 0.50DS) and astigmatism < or = 0.50 diopter cylinder (DC) were 46.8%, 31.0%, 4.3%, 17.9% and 60.4% respectively in the rural population and 29.0%, 17.6%, 1.5%, 51.9%, 59.1% respectively in the urban population. The prevalence of emmetropia decreased with age ( p p = 0.001) and were associated with nuclear sclerosis ( p = 0.001) in both populations. Hyperopia was commoner among women than men ( p = 0.001); was positively associated with diabetes mellitus ( p = 0.008) in the rural population and negatively with nuclear sclerosis ( p = 0.001) in both populations.
  
  
  CONCLUSIONS
  Spectacle use was found to be significantly lower in the rural population. The pattern of refractive errors was significantly different between both populations.
authors.affiliation: Vision Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Raju
authors.initials: R
authors.lastname: Prema
authors.forename: Ronnie
authors.initials: R
authors.lastname: George
authors.forename: Ramesh
authors.initials: R
authors.lastname: Sathyamangalam Ve
authors.forename: Arvind
authors.initials: A
authors.lastname: Hemamalini
authors.forename: Mani
authors.initials: M
authors.lastname: Baskaran
authors.forename: Govindaswamy
authors.initials: G
authors.lastname: Kumaramanickavel
authors.forename: McCarty
authors.initials: M
authors.lastname: Catherine
authors.forename: Lingam
authors.initials: L
authors.lastname: Vijaya
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005139:Eyeglasses / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000453:epidemiology* / Q000628:therapy; D012424:Rural Population / Q000706:statistics & numerical data*; D014505:Urban Population / Q000706:statistics & numerical data*; D014792:Visual Acuity