Size of the neuroretinal rim and optic cup and their correlations with ocular and general parameters in adult Chinese: the Beijing eye study.

AIM

To measure the size of the neuroretinal rim, the major variable in the quantitative analysis of the optic nerve head, and its correlations in adult Chinese in a population based setting.

METHODS

The Beijing eye study-a population based, cross sectional cohort study-included 4439 subjects from among 5324 of age of 40+ years invited to participate (response rate 83.4%). This study included a random sample of 781 subjects with normal intraocular pressure (IOP), normal visual fields, and a normal optic nerve head; and a random sample of 84 subjects with an IOP >21 mm Hg. Colour optic disc photographs (30 degrees ) were examined morphometrically.

RESULTS

In the normal group, the mean (SD) neuroretinal rim area was 1.70 (0.30) mm(2). It was significantly correlated with optic disc area (rim area = 0.43*disc area+0.67; p<0.001). It was not significantly associated with age, sex, or a known diagnoses of diabetes mellitus, arterial hypertension or hypotension, hyperlipidaemia, coronary heart disease, or cerebral haemorrhage.

CONCLUSIONS

In adult Chinese, the neuroretinal rim area measures 1.70 (0.30) mm(2) on optic disc photographs. It is statistically independent of age. Compared with data from studies in Western countries, the neuroretinal rim is larger in adult Chinese than in adult white populations, corresponding to a larger optic disc size in the Chinese.