title: Optic disk size variability between African, Asian, white, Hispanic, and Filipino Americans using Heidelberg retinal tomography.
abstract: OBJECTIVE
  To compare the optic disk size of African, Asian, white, Hispanic, and Filipino-American patients in a multiethnic glaucoma practice.
  
  
  METHODS
  Five hundred seventy-six eyes of 319 patients who had consecutively received Heidelberg retinal tomography 2 (HRT) from February 2006 to October 2007 in a glaucoma clinic that met inclusion criteria were included. The 5 ethnic groups represented were white (n=215, 37.3%), Asian (non-Filipino) (n=178, 30.8%), African (n=67, 11.6%), Hispanic (n=66, 11.4%), and Filipino-Americans (n=50, 8.7%). The relationship of optic disk size (global disk area) with race, age, sex, diagnosis, central corneal thickness (CCT), spherical equivalent refraction (SE), and cylindrical refraction was evaluated using multivariate regression analysis adjusting for confounders.
  
  
  RESULTS
  Mean optic disk size of white-Americans (2.15 mm) was significantly smaller than that of African (2.55 mm), Asian (2.38 mm), Filipino (2.48 mm), and Hispanic-Americans (2.57 mm) (all, P < or = 0.0007). Global disk area was not statistically different between all other races (all, P > or = 0.054). Global disk area increased with SE (P=0.013), but was not found to vary with age, sex, diagnosis, CCT, or cylindrical refraction (all, P > or = 0.08).
  
  
  CONCLUSIONS
  In our glaucoma clinic-based population, white-Americans had smaller optic disks than all other races, and there were no optic disk size differences among the other races studied. Optic disk size had no significant relationship to age, sex, CCT, cylindrical refraction or diagnosis, and a small direct relationship to SE. Confirmation of these results in a population-based study is needed.
authors.affiliation: Department of Ophthalmology, University of California, San Francisco 94143-0730, USA.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Seider
authors.forename: Roland Y
authors.initials: RY
authors.lastname: Lee
authors.forename: Dandan
authors.initials: D
authors.lastname: Wang
authors.forename: Melike
authors.initials: M
authors.lastname: Pekmezci
authors.forename: Travis C
authors.initials: TC
authors.lastname: Porco
authors.forename: Shan C
authors.initials: SC
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D044383:Black People; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000208:ethnology*; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology*; D009929:Organ Size; D010679:Philippines / Q000208:ethnology; D044469:Racial Groups; D012189:Retrospective Studies