[Blocking mechanisms of the pupil and posterior surface of the iris]

After covered fistulizing operations for primary glaucoma without complications the anterior chamber is deeper than it was prior to surgery. This means that the contact between the posterior surface of the iris and the lens may be very important in the pathogenesis of all primiary glaucomas, especially in acute primary glaucoma: an acute iridolenticular block can develop. Severe blocking mechanisms of the posterior surface of the iris sometimes appear after fistulizing glaucoma operations and after cataract extractions (with and without implantation of a pseudophakos) if there is no postoperative dilatation of th pupil. Peripheral iridectomies alone cannot prevent the anterior chamber from becoming shallower or flattened, possibly with the development of malignant glaucoma.