The effects of near-ultraviolet radiation on choroidal blood flow were studied in aphakic rabbit eyes. After lens extraction, eyes were exposed to monochrometic nera-ultraviolet radiation with a wavelength of 365 nm and radiant exposure of 8.0 J/cm2. Choroidal blood flow was measured by the hydrogen clearance method 3, 7 and 14 days after exposure. Eyes were enucleated after the measurement of choroidal blood flow and examined histopathologically. Choroidal blood flow in the eyes wan significantly reduced 7 and 14 days after exposure compared with control eyes. Histopathologically, the photoreceptors showed markde destruction 3, 7 and 14 days after exposure, while the retinal pigment epithelium and choriocapillaris remained intact during this period. These results suggested that choroidal blood flow was reduced by decreased oxygen consumption in the outer retina as a result of the destruction of photoreceptors after exposure to near-ultraviolet radiation.