Experimental studies on cataract.

I have discussed five aspects of lens metabolism and their possible relationship to cataract in man, and this has left me with five fundamental questions to be answered. 1. Are the fluorescent tryptophan derivatives, found only in the lens of man and higher primates, involved in the development of brown nuclear cataract? 2. Is naphthalene cataract in rabbits a model for any type of cataract in man--i.e., are quinones ever formed in the human eye? 3. Is diabetes the only cataract in which osmotic swelling is important? 4. Does self-digestion of protein in the human lens contribute to cataract development? 5. Are the consequences of the abnormal maturation of lens fibers, which occurs in tryptophan deficiency cataract in rats, ever seen in man?