title: Prevention and management of collagen copolymer phakic intraocular lens exchange: causes and surgical techniques.
abstract: OBJECTIVE
  To analyze causes leading to explantation and exchange of Implantable Collamer Lens phakic intraocular lenses (pIOLs) and examine the surgical techniques of pIOL exchange.
  
  
  METHODS
  Wuhan Aier Eye Hospital, Wuhan, China.
  
  
  METHODS
  Retrospective analysis of prospectively collected data.
  
  
  METHODS
  Different techniques were used to explant the pIOLs based on the amount of vaulting. Preoperative and postoperative data were collected to evaluate possible causes leading to pIOL exchange and the safety of pIOL exchange.
  
  
  RESULTS
  Of 616 myopic eyes with previous pIOL implantation, 16 eyes of 15 patients having pIOL exchange were reviewed. Eight surgeries (50%) were performed because of low vaulting (≤100 μm) and another 8 (50%) because of too high vaulting (≥1000 μm). 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 pIOL (<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 pIOL exchange, the vaulting ranged from 162 to 715 μm. No anterior subcapsular cataracts or other complications occurred during the observation period.
  
  
  CONCLUSIONS
  The main causes of abnormal vaulting and subsequent pIOL exchange included a thick crystalline lens, low ACD, too-small pIOL, WTW measurement error, and ciliary body cysts. Phakic IOL explantations were individually designed based on the vaulting to achieve proper safety and efficacy.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors: From the Aier School of Ophthalmology (Zeng), Central South University (Zeng), Changsha, and Wuhan Aier Eye Hospital (Zeng, Xie, Chen), Wuhan, China. Electronic address: zengqingyan1972@163.com.
authors: Qing-Yan
authors: QY
authors: Zeng
authors: From the Aier School of Ophthalmology (Zeng), Central South University (Zeng), Changsha, and Wuhan Aier Eye Hospital (Zeng, Xie, Chen), Wuhan, China.
authors: Xiu-Li
authors: XL
authors: Xie
authors: From the Aier School of Ophthalmology (Zeng), Central South University (Zeng), Changsha, and Wuhan Aier Eye Hospital (Zeng, Xie, Chen), Wuhan, China.
authors: Qian
authors: Q
authors: Chen
mesh_terms: D000328:Adult; D003094:Collagen; D020878:Device Removal; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures; D054120:Phakic Intraocular Lenses; D011446:Prospective Studies; D011475:Prosthesis Failure; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult
chemical_list: D003094:Collagen