THE MECHANISM by which surgical procedures control glaucoma is not known, a fact which is not remarkable since the cause of the disease itself is not known. The present study is an attempt to demonstrate whether gonioscopy can shed light upon this point. Examination was made with the Koeppe lens and binocular gonioscope or with the Allen Gonioprism and slit lamp, the patients being unselected except for their having had fistulizing antiglaucoma operations. After the records with insufficient data or length of follow-up study had been discarded, there remained 91 eyes for analysis, all of which I had personally examined. None was followed for less than six months. All but 7 were followed over one year—48 from one to three years, 17 from three to five years, and 19 over five years.
The generally accepted mode of action of fistulizing operations may best be described by quoting Duke-Elder.1
In