Eighteen patients undergoing glaucoma filtration surgery underwent specular microscopic examination 1 day prior to surgery and 4 to 6 months after surgery. Patients were evaluated postoperatively for the presence of iridocorneal or lenticular-corneal touch, anterior chamber depth, and inflammation. Ten eyes that maintained their anterior chamber following glaucoma filtration surgery did not have a significant decrease in corneal endothelial cell density. However, eight eyes that developed a shallow anterior chamber with iridocorneal touch had a mean (+/- SD) decrease of 265 +/- 185 cells (12.4%) peripherally and 250 +/- 243 cells (11.6%) centrally in corneal endothelial cell count. None of the patients with iridocorneal touch developed corneal edema after a mean follow-up of 44.4 +/- 18.0 months. Iridocorneal touch after glaucoma filtration surgery is associated with loss of endothelial cells yet appears to be well tolerated by the cornea.