• Temperature measurements were taken from (1) the retina-choroid in the macula, (2) the scleral surface, or (3) the bulbar conjunctiva of the cynomolgus monkey, while the fellow eye was exposed to a moderate-intensity light source. Light stimulation produced an increase in tissue temperature in the nonlight-stimulated eye. The increase in tissue temperature presumably results from a reflexive increase in choroidal blood flow. Hydrogen washout measurements of blood flow in the retina-choroid confirmed this increase in flow. This active mechanism, along with the passive ability of the choroidal circulation to dissipate light-generated heat, may be an important physiologic safeguard in helping to maintain a stable temperature environment for the outer retinal layers in the macula.
Leonard M. Parver, Charles R. Auker, David O. Carpenter, Thomas Doyle. Choroidal Blood FlowII. Reflexive Control in the Monkey. Arch Ophthalmol. 1982;100(8):1327–1330. doi:10.1001/archopht.1982.01030040305021