Optic disc, rim and peripapillary chorioretinal atrophy in normal Japanese eyes: the Kumejima Study

To report reference data for optic disc, neuroretinal rim and β-peripapillary atrophy (β-PPA) in normal Japanese.

In the Kumejima study, all participants underwent disc stereo-photography; 2208 normal subjects had good-quality disc stereo and β-PPA photographs OU. The disc and rim area and the area and angular extent of β-PPA were evaluated by computer-assisted planimetry.

The disc, rim, and β-PPA area and its angular extent OD (OS) averaged 2.54 ± 0.50 (2.53 ± 0.49), 1.67 ± 0.29 (1.67 ± 0.30), 0.47 ± 0.66 (0.42 ± 0.59) mm², and 99 ± 85 (92 ± 82) degrees (mean ± standard deviation) with bilateral Pearson's correlation coefficient of 0.890, 0.769, 0.679 and 0.632 (P < 0.001), respectively, while the 95th percentiles of the absolute inter-eye differences were 0.48, 0.41, 0.96 mm², and 153°. The correlation coefficient between β-PPA area and its angular extent was 0.963 (P < 0.001). Age showed negative correlation with the rim area and positive correlation with β-PPA area (P < 0.001). Among ocular factors, disc area showed positive correlation and intraocular pressure negative correlation with the rim area (P ≤ 0.001), axial length and disc area positive correlation with β-PPA area (P < 0.001 and P = 0.051).

The averages and distribution of the optic disc and rim area, β-PPA area and its angular extent in normal Japanese are reported, which will facilitate screening of glaucoma in Japanese. In normal Japanese eyes, the disc size and intraocular pressure significantly correlated with the rim area, and the axial length with β-PPA area.