[Tonometry and tonography for open Schlemm's canal (author's transl)]

In 13 eyes tonometry was performed during trabeculotomy at the beginning, after preparation of the outer scleral lamella and after the excision of the outer wall of the canal of Schlemm. In 4 eyes this was combined with tonography. There was no significant change of the averaged i.o. pressure and the resistance to aqueous outflow. Thus in primary open angle glaucoma the resistance to aqueous outflow must be located primarily in the trabecular meshwork.