Purpose: To study the optic disc characteristics using the Heidelberg Retina Tomograph (HRT) II in normal Japanese subjects.
Methods: A total of 1060 eyes of 530 normal subjects with reliable HRT images, who participated in the community health checkup in the city of Akita, Japan, were included in the study. Optic disc parameters were obtained using the HRT II. Sex, age, height, weight, blood pressure, ocular perfusion pressure, hemoglobin A1c status, intraocular pressure, and disc area with HRT parameters were assessed using correlation and multiple regression analysis.
Results: Disc area and cup area averaged 2.04±0.44 mm2 (mean±standard deviation) and 0.51±0.34 mm2, respectively. There were no significant differences in parameters between right and left eyes. Males had significantly greater cup area, cup volume, cup/disc ratio than females (P<0.001) and smaller rim area and rim volume. Disc area was strongly correlated with all HRT parameters. Age had moderate correlations with several tomographic parameters in multiple regression analysis, whereas blood pressure, ocular perfusion pressure, intraocular pressure, hemoglobin A1c, height, and weight had weak or no correlations.
Conclusions: This study provided a range of normal HRT II optic disc parameters for Japanese subjects. Compared with data from studies on other races, the mean disc area and cup area of Japanese subjects were between that of African Americans and white subjects. Given the significant differences between males and females, a normative database of HRT II variables should be established by sex.