Age-related decline of retinal oxygen extraction in healthy subjects

Abstract

Purpose : The aim of the present study was to analyze the age-dependence of total retinal blood flow and total retinal oxygen extraction in healthy subjects and correlate these parameters to structural parameters as measured with optical coherence tomography (OCT).

Methods : Sixty-eight healthy subjects were included in the present study. Total retinal oxygen extraction was calculated based on measurement of total retinal blood flow using bidirectional Doppler OCT and measurement of oxygen saturation using spectroscopic reflectometry. Retinal nerve fiber layer thickness was measured using OCT and the total number of retinal ganglion cells was calculated based on a previously published model. Correlation of these parameters with age was studied and the association between structural OCT parameters and hemodynamic parameters was calculated.

Results : The average age of the patients was 45.6 years. Structural OCT parameters as well as retinal hemodynamic parameters showed a significant decrease with age. The correlation coefficients were between r = -0.25 and r = -0.41. Structural OCT parameters and hemodynamic parameters were significantly correlated. The strongest association was found between total retinal oxygen extraction and the calculated number of retinal ganglion cells (r = 0.75, p < 0.001).

Conclusions : The present study shows an age-related decline of retinal oxygen extraction. Values of retinal oxygen extraction are correlated to retinal nerve fiber layer thickness and number of retinal ganglion cells. Our data partially explain the wide inter-individual variability in retinal blood flow values in healthy subjects. Longitudinal studies are required to study the time course of vascular and neuronal loss in humans.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.