Retinal oxygen saturation in Chinese adolescents

Abstract

Purpose: To study the retinal oxygen saturation in normal eyes of Chinese adolescents. Methods: Performing retinal oximetry with the Oxymap T1 Retinal Oximeter in healthy children and adolescents (aged 5–18 years old), we measured the arterial (SaO2) and venular (SvO2) oxygen saturation and the arteriovenous difference in oxygen saturation (Sa-vO2). Results: The study included 122 individuals with a mean age of 13.0 ± 2.9 years (range: 5–18 years) and a mean refractive error of −3.25 ± 2.49 dioptres (range:−8.88 to +3.13 dioptres). Mean SaO2, SvO2 and Sa-vO2 was 85.5 ± 7.1%, 48.2 ± 5.5% and 37.3 ± 6.5%, respectively. Mean SaO2 was significantly (p < 0.001) the lowest in the inferotemporal quadrant (79.1 ± 9.0%), followed by the superotemporal quadrant (83.4 ± 9.7%), the inferonasal quadrant (90.4 ± 10.6%) and the superonasal quadrant (93.4 ± 10.8%). In a similar manner, the values of the SvO2 were the lowest (p < 0.001) in the inferotemporal quadrant (42.1 ± 8.3%), followed by the superotemporal quadrant (47.8 ± 7.2%), the inferonasal quadrant (52.3 ± 8.4%) and the superonasal quadrant (55.1 ± 7.6%). Arteriovenous difference in oxygen saturation (Sa-vO2) did not differ significantly (all p > 0.05) between the fundus quadrants. In multiple linear regression analysis, SaO2 increased (regression coefficient r2= 0.28) with older age (standardized regression coefficient β: 0.23; p = 0.01) and more myopic refractive error (β: −0.39; p < 0.001). Higher SvO2 was significantly correlated with more myopic refractive error (β: −0.46; p < 0.001; r2= 0.20), while Sa-vO2 increased significantly only with older age in the multivariate analysis (β: 0.26; p = 0.01; r2= 0.07). Conclusions: Our study provides normative data for Chinese children and adolescents who showed lower values than adults for SaO2 and SvO2. SaO2 increased with older age and higher myopic refractive error, SvO2 increased with higher myopic refractive error, and Sa-vO2 increased with older age.