Data are presented on the effects of oxygen at 2.36 and 3.70 atmospheres on retinal venous oxygen saturation, retinal vessel size, and retinal mean circulation time as measured by photographic techniques. Retinal venous oxygen saturation is found to increase with increase of inspired oxygen tension (PO2). Vessel size becomes progressively smaller at higher PO2 and retinal mean circulation time is prolonged. If retinal oxygen consumption is not altered by exposure to high PO2, it is suggested that at these pressures the choriocapillaris is supplying part of the oxygen previously delivered by the retinal circulation and that the retinal blood flow is reduced proportionately more than the flow in the choriocapillaris.
Frayser R, Saltzman HA, Anderson B, Hickam JB, Sieker HO. The Effect of Hyperbaric Oxygenation on Retinal Circulation. Arch Ophthalmol. 1967;77(2):265-269. doi:10.1001/archopht.1967.00980020267023