Retinal Oximetry in a Healthy Japanese Population

PURPOSE: To establish the normative database of retinal oximetry using Oxymap T1 in a healthy Japanese population, and study the reproducibility of the measurements in Japanese. METHODS: We measured oxygen saturation in the major retinal vessels with Oxymap T1 in 252 eyes of 252 healthy Japanese subjects. Fundus images acquired using Oxymap T1 were processed using built-in Oxymap Analyzer software. Reproducibility of retinal oximetry was investigated using 20 eyes of 20 healthy subjects. RESULTS: The mean retinal oxygen saturation of 4 quadrants in healthy Japanese was 97.0 ± 6.9% in arteries and 52.8 ± 8.3% in veins. The mean arteriovenous difference in oxygen saturation was 44.2 ± 9.2%. Both arterial and venous oxygen saturation were significantly lower in the temporal side of the retina, especially in the temporal-inferior vessels. However, the arteriovenous difference in oxygen saturation was limited in the 4 quadrants. Interphotograph, intervisit, and interevaluator intraclass correlation coefficients were 0.936–0.979, 0.809–0.837, and 0.732–0.947, respectively. In the major retinal arteries, oxygen saturation increased with age (r = 0.18, p<0.01), at a rate of 0.67% per 10 years. However, venous oxygen saturation showed no correlation with age. CONCLUSIONS: This study provides the normative database for the Japanese population. The arterial saturation value appears to be higher than other previous studies. Mean retinal oximetry in 4 quadrants with Oxymap T1 has high reproducibility.