Purpose: To assess the neuroretinal rim shape in a population-based study.
Design: Population-based, cross-sectional cohort study.
Methods: The Beijing Eye Study included 4,439 subjects with an age of 40+ years. On color optic disk photographs of a random sample of 92 subjects (92 eyes), neuroretinal rim width and area were measured in different disk sectors.
Results: The neuroretinal rim was significantly (P = .038) wider in the inferior disk region (0.52 +/- 0.11 mm) than in the superior disk region (0.49 +/- 0.10 mm), where it was significantly (P < .001) wider than in the nasal disk region (0.47 +/- 0.09 mm) and was significantly (P < .001) the smallest in the temporal disk region (0.40 +/- 0.12 mm). The rim was significantly wider inferiorly ("I"), followed by the superior disk region ("S"), the nasal disk region ("N"), and finally the temporal disk region ("T") [ISNT] rule defined as the rim being larger inferiorly than superiorly, being larger than nasally and being larger than temporally, was fulfilled in 48 (52%) subjects.
Conclusions: In adult Chinese as in Caucasians, the neuroretinal rim usually follows the ISNT rule.