Haptic breakage following neonatal IOL implantation in a nonhuman primate model

To evaluate the long-term safety of implanting intraocular lenses (IOLs) in neonatal eyes using a nonhuman primate model, a one-piece all-polymethylmethacrylate (PMMA) IOL was implanted into the posterior chamber of 21 neonatal Rhesus monkey eyes following a lensectomy and anterior vitrectomy. These monkeys then were monitored for 26 to 40 months for complications. The eyes from seven monkeys were studied histopathologically. One or both haptics broke on 7 of the 21 (33%) IOLs in a mean of 21 months (range 6 to 31 months) after their implantation. Only one of the haptics from these seven eyes was found to be in the capsular bag when these eyes were studied histopathologically. Nine haptics had eroded into the iris leaflets, two into the ciliary body, and one into the anterior chamber. One additional haptic was in the sulcus. The haptics of one-piece all-PMMA IOLs may break if implanted in neonatal eyes. A number of factors likely contributed to haptic breakage in these eyes, including an increased number of reoperations, malpositioning of IOL haptics, rapid circumferential and axial growth, and the formation of large Soemmerring's rings.