Syphilis, rheumatism, gout, auto-intoxication and many other constitutional disorders are well recognized agencies which induce sclerosis in body tissues, so there can be little doubt that these conditions produce pathological sclerosis of the meshwork of the iris angle. Psychic disturbances, congested portal or renal system, hard mental or muscular work, etc., etc., induce increased pressure of the general circulation, and so simultaneously the intra-ocular pressure.
According to the edema theory advanced by Fischer, glaucoma is "essentially an edema of the eyeball, and for its production we must hold responsible the same circumstances which are responsible for a state of edema in any other part of the body." The magnificent experimental work of this investigator has shown that edema is nothing more or less than an increased capacity of the protein colloid tissues for water; that the most important factor leading to this increased hydration capacity is an abnormal production or accumulation of acid content, effected by those agencies which are instrumental in causing sclerosis and an increase of blood pressure.
It seems that both of these theories afford an explanation for many of the secondary pathological manifestations which characterize the intra-ocular tissues during a glaucomatous onset.
Fischer criticizes the Henderson theory on the ground that increased blood pressure alone does not lead to edema—edema is thwarted by high blood pressure. On the other hand, if Fischer believes that sclerosis of the meshwork of the iris angle is a result and not a cause of glaucoma, then it would seem that Henderson has the better of the argument. The physiological changes in this structure, which take place with advancing age, can rightfully be looked upon as a predisposing factor in glaucoma.
Dr. Jackson has presented all other phases of this part of the symposium in such a comprehensive manner that nothing further remains to be said.