The physiologic and pharmacologic factors protecting the lens transparency and the update approach to the prevention of experimental cataracts: a review.

In this review some of the so far identified mechanisms implicated in experimental and human cataractogenesis are reviewed. The oxidative insult, the osmotic insult (sugar cataracts and ionic imbalance cataracts), the role of tryptophan, of lysophosphatidylcholine and docohexanoic acid in primary and secondary cataracts are summarized. It is not always possible to identify the primary effect of cataractogenic mechanisms: the human "idiopathic" cataract is probably a multifactorial disease. In the aging lens and under stress conditions (osmotic and oxidative) the physiologic defense systems of the lens appear to be inadequate. Even if conditions of avitaminosis aren't the cause of deterioration of the adult human lens, it has been demonstrated that the supplementation or the deficiency of some nutritional factors may influence the course of cataract.