Optic Disk Size Variability Between African, Asian, White, Hispanic, and Filipino Americans Using Heidelberg Retinal Tomography

Purpose: To compare the optic disk size of African, Asian, white, Hispanic, and Filipino-American patients in a multiethnic glaucoma practice. Patients and 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(2)) was significantly smaller than that of African (2.55 mm(2)), Asian (2.38 mm(2)), Filipino (2.48 mm(2)) and Hispanic-Americans (2.57 mm(2)) (all, P <= 0.0007). Global disk area was not statistically different between all other races (all, P >= 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 >= 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.