We investigated the clinical outcome in two groups of patients who had an extracapsular cataract extraction and implantation of a heparin-surface-modified intraocular lens (HSM IOL) (Group 1) or a conventional poly(methyl methacrylate) (PMMA) lens (Group 2). Nineteen patients in Group 1 had bilateral cataract extraction with implantation of an HSM IOL in one eye and a conventional lens in the fellow eye. All patients had glaucoma, diabetes, or uveitis. Over the long term, there was no statistically significant difference between groups in visual acuity, corneal edema, anterior chamber reaction, and amount of posterior synechia formation and IOL deposits. Yet short-term clinical evaluation revealed significantly less reaction in eyes with the HSM IOL than in those with the PMMA lens. In patients with both lens types implanted, early postoperative anterior chamber reaction was less and IOL deposits fewer in the eye with the HSM IOL.