Retinal Venous Oxygen Saturation Unaltered With Age

Abstract

Abstract: : Purpose: To examine the effect of age on retinal venous blood oxygen saturation and retinal oxygen extraction under normoxic and hypoxic conditions. Methods: All procedures were approved by an IRB, and informed consent obtained. Thirty-two oximetry images were obtained in 14 normal healthy adults (24 -52 years, mean 32, SD 8; 12 male, 20 female, 8 smoker, and 24 non-smoker), retinal artery and vein blood oxygen saturation (O2sat) was measured by a newly developed digital retinal oximeter while breathing room air, and a mixture of room air and nitrogen. During hypoxia, arterial saturations were reduced to approximately 90%. Oxygen extraction was calculated as arterial O2sat – venous O2sat. Venous O2sat and retinal oxygen extraction were compared to age by linear regression analysis, with p < 0.05 considered significant. Results: There was no significant correlation between age and retinal oxygen dynamics. The insensitivity of retinal oxygen delivery to age was consistent regardless of sex or smoking status. Conclusions: While breathing room air, and in response to hypoxia, venous O2sat and retinal extraction of oxygen remain consistent throughout adult life in healthy eyes.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, S • retina • hypoxia