Safety of posterior chamber phakic intraocular lenses for the correction of high myopia - Anterior segment changes after posterior chamber phakic intraocular lens implantation

Objective: To assess the safety of posterior chamber phakic intraocular len s (PCPIOL) implantation in patients with high myopia. Design: Prospective, noncomparative, interventional case series. Participants: Twenty eyes of 10 patients were included. Intervention: Staar Collamer Implantable Contact Lens PCPIOLs were implante d for the correction of high myopia. Main Outcome Measures: Intra- and postoperative complications were recorded . Specular microscopy, lens fluorophotometry, laser flare-meter, and ultras ound biomicroscopy were performed before surgery and at different stages of the follow-up period to evaluate endothelial cell density, crystalline len s transmittance, aqueous flare, and anatomic relations of the implanted len ses with the other structures of the anterior segment. Results: There were no intraoperative complications. One patient experience d pupillary entrapment by the lens in the immediate postoperative period, w hich was resolved without incident. Pigmentary dispersion or cataracts did not appear during the postoperative period. All the lenses remained correct ly centered, and no patient reported night halos or glare. Anterior chamber depth showed a statistically significant reduction, between 9% and 12%. Ce ntral endothelial density was significantly decreased after surgery. The pe rcentages of cell loss after 3, 6, 12, 18, and 24 months were 4.41%, 4.83%, 5.17%, 5.46%, and 6.57%, respectively. Aqueous flare increased by 49.19% i n the first postoperative month in relation to preoperative values. Afterwa rd, it decreased and then remained above preoperative values for the entire follow-up period (33.76% at month 3, 27.81% at month 6, 27.65% at month 12 , 23.39% at month 18, and 27.27% at month 24), Crystalline lens transmittan ce decreased by 0.72% at month 3, by 1.44% at month 6, by 1.95% at month 12 , by 2.25% at month 18, and by 2.24% at month 24. Finally, by ultrasound bi omicroscopy it was observed that the PCPIOL and the crystalline lens were i n contact on the peripheral level in 12 patients (60%) and in the center in another three patients (15%) during at least one checkup. In all the patie nts, contact between the PCPIOL and the posterior iris surface could be obs erved. Conclusions: Posterior chamber phakic IOL implantation for the surgical cor rection of high myopia is a safe procedure with regard to immediate visual and refractive results. The short-term clinical benefit and lack of immedia te surgical complications are impressive. However, the increase in flare, t he endothelial cell loss, the decrease in crystalline lens transmittance, a nd the iris-PCPIOL and crystalline lens-PCPIOL contact are findings that su ggest caution regarding the long-term safety of this lens implant. Ophthalm ology 2001;108:90-99 (C) 2001 by the American Academy of Ophthalmology.