title: Cup-to-disc ratios of Aboriginal and non-Aboriginal youths.
abstract: BACKGROUND
  The determination of the cup-to-disc ratio (C/D) is a standard procedure in an eye examination and is pivotal in the diagnosis of glaucoma. Determining the size of the C/D ratios of different races of young people may be helpful in determining the genetically predetermined differences between Aboriginal and non-Aboriginal people. The aim of this study was to determine whether there is a statistically significant difference in the average C/D ratios of young Aboriginal and non-Aboriginal people.
  
  
  METHODS
  The overall average C/D ratios of 104 subjects aged between five and 23 years were compared for two age-matched groups by stereoscopic indirect ophthalmoscopy. Differences between the overall average C/D ratios of the two groups were assessed for significance using an unpaired Student's t test.
  
  
  RESULTS
  While the range of C/D ratios within each group was the same (zero to 0.7), there was a statistical difference (p < 0.001) between the overall average C/D ratios of the Aboriginal (C/D = 0.295) and non-Aboriginal (C/D = 0.159) groups.
  
  
  CONCLUSIONS
  Results indicating a difference between the overall average C/D ratios between Aboriginal and non-Aboriginal young people may have implications for initial assessments of glaucoma in patients of any age.
authors.affiliation: Patrick Gerry Optometrists, Brisbane, Queensland, Australia. pat@pgo.com.au
authors.forename: Patrick
authors.initials: P
authors.lastname: Gerry
authors.forename: Kate
authors.initials: K
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005123:Eye / Q000196:embryology*; D005260:Female; D005901:Glaucoma / Q000175:diagnosis; D006801:Humans; D008297:Male; D009898:Optic Disk / Q000033:anatomy & histology*; D012424:Rural Population / Q000706:statistics & numerical data*