Abstract
Purpose :
Ischemic retinopathies show topographical patterns and the macula is preferentially affected in many cases such as in diabetic macular edema and age related macular degeneration. We examine topographical aspects of retinal oxygen metabolism in the hope that these may underlie the topographical expression of ischemic retinal disease. The purpose of the study was to evaluate the macular oxygen metabolism and compare to peripheral parts of the retina.
Methods :
Retinal vessel oxygen saturation was measured with a retinal oximeter (Oxymap T1, Oxymap ehf., Reykjavik, Iceland) in 15 healthy individuals. The images were acquired with the macula located in the center of the images. Analyzed vessels were categorized as either macular vessels or peripheral vessels (all in the temporal side of the retina, see Figure).
Results :
Retinal oxygen saturation was higher in macular arterial and venous branches compared to peripherial branches. Oxygen saturation in arterioles was 96%±4% in macular branches and 90%±5% in peripheral branches (p=0.0007, mean±standard deviation). Oxygen saturation in venules was 76%±3% in macular branches vs. 50%±7% in peripheral branches ( p<0.0001). Arteriovenous difference in oxygen saturation was lower in macular area, 20%±4% compared to the periphery, 41%±2%, p<0.0001.
Conclusions :
Oxygen saturation is dramatically different in macular vessels compared to peripheral branches. This suggests substantial differences in oxygen metabolism between the macula and peripheral parts of the retina. It remains to be seen whether these differences play a role in disease patterns and why the macula is so susceptible to disease.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.