The role of inflammation in radiation cataractogenesis

Studies were designed to assess the contribution of X-ray-induced intraocular inflammation to radiation cataractogenesis in the rat and the rabbit eye. In the rat it was observed that only X-ray doses exceeding 18 Gy produced ocular changes consistent with uveitis beginning 1-4 days post-irradiation. Low to moderate cataractogenic doses failed to produce such changes. In the rabbit eye a 10 Gy single dose of X-rays induced inflammation and cataract. The same dose when divided into ten 1 Gy daily fractions was non-inflammatory yet produced cataracts similar in appearance and time of onset to that induced by a single tenfold higher X-ray dose. These and additional studies using endotoxin-induced uveitis suggest that inflammation is not essential to the development of X-ray cataract. (author)