Production of Lenticular Opacities by Ultraviolet Radiation in the Presence of Certain Salts

The results of Hess 1 were confirmed by the production of a surface destruction of the lens epithelium following exposure of the eyes of frogs to ultraviolet radiation. Burge 2 showed that lens material in a test tube was more readily coagulated if salts or sugar were present, because the lens protein was so modified that radiations of short wave-length could precipitate it. He was also able to produce cataracts in the eyes of fish which had been kept in salt solutions for varying periods of time before they were exposed to ultraviolet radiation. (Burge. 3 )

In our experiments, 3 types of procedure were followed: exposure of excised lenses in salt solutions, exposure of the eyes of intact living frogs to direct radiation, in some cases, following the injection of salt solutions into the dorsal lymph sac, and exposure of the lenses of developing chick embryos. In each case, the unscreened radiation of a Cooper-Hewitt quartz mercury-vapor arc was used.

In the first series, the excised lenses of dogs, chickens, and a frog, were exposed directly to the radiation in 0.1% and 1.0% solutions of NaCl and CaCl_2. Controls of lenses exposed in Ringer's solution and of unexposed lenses in salt solution were used. The results of these experiments may be summed up as follows: the lenses of dogs exposed for 22-50 minutes at a distance of 25 cm. from the center of the arc, in 1.0% NaCl showed no change in opacity, but slight surface degeneration appeared. (These dogs had been anesthetized for use in other experiments.) The chick material consisted of lenses of young chicks and adult hens, and was used immediately after removal from the animals, except in 2 cases where the material was kept on ice for a few hours before exposures could be made.