Retinotoxic and choroidotoxic substances.

Four separate examples have been discussed with the object of showing, first, how the concept of toxic amblyopia is an irrelevant one for modern ophthalmic research. This is the more true since one large category of the classical toxic amblyopias is not toxic at all and further adds to the confusion. It is suggested that rigorous criteria for the causative role of a particular substance in toxic phenomena be adopted. It is further suggested that since the ever increasing number of toxic substances act by widely different mechanisms on different parts of the retina and choroid, and since our knowledge of these mechanisms can be obtained in some detail by modern experimental methods, each of these toxic entities be considered separately and on its own merits unless one is dealing with two effects which are experimentally demonstrable to be identical. Only if this type of procedure is followed, can we pursue a logical experimental course from toxic effect to mechanism to rational therapy.