Ultrastructural lens changes in X-ray induced cataract of the rat.

The effect of in vivo X-irradiation on the ultrastructure of the rat lens was investigated by electron microscopy. The left eye of each animal was exposed to a single dose of 1500 r of X-rays, while the other parts of the body were protected by a lead shield. The protected eye served as a control. Samples of the lenses were taken for electron microscopical examination at intervals of 3, 7, 30, 60, 90 and 180 days after the irradiation. The first ultrastructural changes induced by X-rays were found after three days in the epithelial cells which became vacuolated. After seven days these cells showed marked oedema and after six months the whole epithelium was shrunken. The most prominent changes in the lens fibres were swelling and vacuolization. No alterations were noted in the lens capsule. The first visible opacities of the lens were found ninety days after irradiation under the posterior capsule and three months later the entire lens was totally opaque.