Theoretical estimation of retinal oxygenation during retinal artery occlusion

The aim of the present work was to simulate the oxygenation of the whole retina under normal conditions as well as during retinal ischemia. A differential equation describing how oxygen is transported from blood to tissue, diffuses through the tissue and is consumed according to Michaelis-Menten kinetics was constructed. The outer retina was divided into three regions of which one was set to have consumption. The inner retina was considered as one uniform region with respect to maximal rate of oxygen consumption and blood flow. The results suggest that extreme hyperoxia would be needed to make the choroid capable of supplying the whole retina during total retinal artery occlusion and moreover confirm that light might to some extent be beneficial. As supplying 100% oxygen by nose cannula or common oxygen mask can hardly increase the arterial oxygen tension to the levels needed to rescue the whole retina, the effects of oxygen treatment of total retinal artery occlusion are expected to be modest, both in darkness and light, unless a non-rebreather face mask system is used.