One hundred fifty-one unilateral cataract patients were randomly assigned to receive either a one-piece Staar AA-4203 silicone intraocular lens inserted through a 3.5 mm incision, an loptex 5 mm x 6 mm oval optic lens inserted through a 5.5 mm incision, or an AMO three-piece modified C-loop 6.0 round optic poly(methyl methacrylate) lens inserted through a 6.5 mm incision. Follow-up was 97% at two days postoperatively and 84% at one week and two months postoperatively. At one week postoperatively, 62% of 3.5 mm incision cases had uncorrected visual acuity of 20/40 or better compared with 33% of 5.5 mm (P < .01) and 43% of 6.5 mm incision cases. At two months postoperatively, 85% of 3.5 mm incision cases had uncorrected visual acuity of 20/40 or better compared with 64% of 6.5 mm (P < .05) and 71% of 5.5 mm incision cases. The 3.5 mm incision cases had significantly less total keratometric cylinder than other cases at all postoperative examinations (P < or = .001) and less surgically induced cylinder at two days and one week post-operatively (P < or = .02). The 5.5 mm and 6.5 mm incision cases did not differ significantly in visual acuity or astigmatism at any examination.