In pigmentary glaucoma, reverse pupillary block is one mechanism presumed possible for backward bowing of the iris leading to iris-zonular rubbing. Therefore, increasing numbers of patients are being treated by laser iridotomy. We demonstrate five patients with pigmentary glaucoma whose iris configuration was examined by high-resolution ultrasound biomicroscopy before and after laser iridotomy. Of these patients, three had a severe case of posterior iris bowing with iris-zonular rubbing. In these cases, the ultrasound biomicroscope revealed an anterior motion of the iris diaphragm after iridotomy. The other two patients had no direct iris-zonular contact and displayed a normal iris curvature that did not change after iridotomy. YAG-laser iridotomy is a prophylactic treatment in pigmentary glaucoma for a subgroup of patients in whom an iris concavity with iris-zonular rubbing can be demonstrated by high-resolution ultrasound or equivalent methods.