A prospective randomized study was conducted in 137 patients who underwent cataract surgery and implantation of a polymethylmethacrylate intraocular lens with either polyacrylamide (Orcolon) (68 patients) or sodium hyaluronate (Healon) (69 patients) as the viscoelastic material. Both viscoelastics were aspirated at the end of surgery. Patients were examined before surgery and 1 and 14 days after surgery. Endothelial cell counts were obtained before surgery and 3 months after surgery in 34 patients (16 in the polyacrylamide group and 18 in the sodium hyaluronate group). There were no reports of a flat or shallow anterior chamber intraoperatively in either group. There was no statistically significant difference between the two groups in the incidence of corneal edema or iritis on any visit or in endothelial cell loss. Although there was a significant reduction in intraocular pressure across postoperative visits for the overall sample, there was no significant difference in pressure between the polyacrylamide and sodium hyaluronate groups. The results indicate that no untoward effects on corneal edema, endothelial cell count, iritis or intraocular pressure are to be expected when polyacrylamide is used as an aid to cataract surgery.