Prevention and management of collagen copolymer phakic intraocular lens exchange: Causes and surgical techniques

PURPOSE: To analyze causes leading to explantation and exchange of Implantable Col lamer Lens phakic intraocular lenses (pIOLs) and examine the surgical techniques of plOL exchange. SETTING: Wuhan Aier Eye Hospital, Wuhan, China. DESIGN: Retrospective analysis of prospectively collected data. METHODS: Different techniques were used to explant the plOLs based on the amount of vaulting. Preoperative and postoperative data were collected to evaluate possible causes leading to plOL exchange and the safety of plOL exchange. RESULTS: Of 616 myopic eyes with previous plOL implantation, 16 eyes of 15 patients having plOL exchange were reviewed. Eight surgeries (50%) were performed because of low vaulting 100 [In) and another 8 (50%) because of too high vaulting ( 1000 gm). The causes leading to low vaulting included increased crystalline lens thickness (>= 4.0 mm), low anterior chamber depth (ACD) (<3.1 mm), and a too-small plOL (<12.0 mm). The high vaulting was primarily the result of oversized white-to-white (WTW) measurements with Scheimpflug pachymetry (Pentacam) or the use of a digital caliper by an unskilled examiner and of ciliary body cysts. Six months after plOL exchange, the vaulting ranged from 162 to 715 pm. No anterior subcapsular cataracts or other complications occurred during the observation period. CONCLUSIONS: The main causes of abnormal vaulting and subsequent plOL exchange included a thick crystalline lens, low ACD, too-small plOL, WTW measurement error, and ciliary body cysts. Phakic IOL explantations were individually designed based on the vaulting to achieve proper safety and efficacy. (C) 2015 ASCRS and ESCRS