title: Ocular axial length and its associations in an adult population of central rural India: the Central India Eye and Medical Study.
abstract: OBJECTIVE
  To investigate the normal distribution of axial length of the globe, which is a major measurement of the eye, and its associations with other ocular and systemic parameters.
  
  
  METHODS
  Population-based study.
  
  
  METHODS
  The Central India Eye and Medical Study is a population-based study performed in a rural region of central India. The study comprised 4711 subjects (aged 30+ years) of 5885 eligible individuals (response rate, 80.1%).
  
  
  METHODS
  A detailed ophthalmic and medical examination was performed. The axial length was measured sonographically.
  
  
  METHODS
  Axial length.
  
  
  RESULTS
  Axial length measurements were available on 4698 study participants (99.7%). Their mean age was 49.4+/-13.4 years (range, 30-100 years), and the mean refractive error was -0.18+/-1.48 diopters (range, -20.0 to +7.25 diopters). Mean axial length was 22.6+/-0.91 mm (range, 18.22-34.20 mm). In multivariate analysis, axial length was significantly (P<0.001) associated with the systemic parameters of increased age, taller body height, greater body mass index, and higher level of education, and with the ocular parameters of lower best-corrected visual acuity, lower corneal refractive power, deeper anterior chamber, thicker lens, and more myopic spherical power and cylindrical refractive power. Within the highly myopic group, as defined by an axial length that exceeded 26.5 mm, none of these associations (except for the association between axial length and spherical refractive power) were statistically significant (P>0.15) in univariate or multivariate analysis.
  
  
  CONCLUSIONS
  In a rural population of central India, the mean ocular axial length was 22.6+/-0.91 mm, which was shorter than that of other populations. Axial length was associated with the systemic parameters of increased age, taller body height, greater body mass index, and a higher level of education, and with the ocular parameters of lower best-corrected visual acuity, lower corneal refractive power, deeper anterior chamber, thicker lens, and more myopic spherical and cylindrical refractive power. These associations were valid only for those eyes that were not highly myopic, whereas axial length was associated with refractive error only in highly myopic eyes.
  
  
  BACKGROUND
  Proprietary or commercial disclosure may be found after the references.
authors.affiliation: Suraj Eye Institute, Nagpur, Maharashtra, India.
authors.forename: Vinay
authors.initials: V
authors.lastname: Nangia
authors.forename: Jost B
authors.initials: JB
authors.lastname: Jonas
authors.forename: Ajit
authors.initials: A
authors.lastname: Sinha
authors.forename: Arshia
authors.initials: A
authors.lastname: Matin
authors.forename: Maithili
authors.initials: M
authors.lastname: Kulkarni
authors.forename: Songhomitra
authors.initials: S
authors.lastname: Panda-Jonas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D001837:Body Weights and Measures; D003430:Cross-Sectional Studies; D016021:Epidemiologic Studies; D005123:Eye / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012030:Refractive Errors / Q000503:physiopathology; D012424:Rural Population / Q000706:statistics & numerical data; D014792:Visual Acuity / Q000502:physiology