Effect of beta-irradiation by a 106 ruthenium plaque on the rabbit eye choroid.

Fourteen Chinchilla gray rabbit eyes were treated with a ruthenium plaque, receiving 200, 400, or 800 Gy, to assess the effect of beta-irradiation on the normal rabbit choroid. Radiation effects were evaluated using fundus photography, fluorescein angiography, fluorophotometry, and histology. Fluorophotometry showed a fluorescein leakage into the vitreous 1 day after irradiation. Leakage values returned to normal within 1 month after irradiation. Fluorescein angiography showed nonperfusion of the choroid after beta-irradiation; the time between irradiation and the onset of nonperfusion was found to be dose dependent. Five months after 200 Gy irradiation, choroidal atrophy had developed but some vessels still stained with fluorescein; 400 Gy irradiation induced subtotal choroidal nonperfusion within 3 months and 800 Gy within 1 week.