We retrospectively studied 348 cases of secondary lens implantation, comparing data obtained from 234 eyes that received anterior chamber intraocular lenses (AC-IOLs) with 114 that received posterior chamber lenses (PC-IOLs), with a mean follow up of 19.5 months (range, 2 to 77 months). Visual acuity was similar in these two groups both before (P = .278) and after surgery (P = .771). Overall, 83% of the eyes had a postoperative acuity of 20/40 or better. In the eyes without preexisting pathology, 93% of those with AC-IOLs and 91% of those with PC-IOLs had this level of postoperative acuity. The incidence of complications in these two groups did not differ significantly. Our study suggests that one-piece flexible open-loop AC-IOLs pose no greater threat than PC-IOLs with respect to visual outcome in secondary implantation. Careful preoperative evaluation of the cornea, retina, and vitreous face will allow selection of the optimum lens style.