Korean Journal of Ophthalmology 2008;22:228-235 ISSN : 1011-8942 DOI : 10.3341/kjo.2008.22.4.228 Clinical Efficacy and Complications of Intraocular Lens Exchange for Opacified Intraocular Lenses Seung Mo Kim, MD, Sangkyung Choi, MD Department of Ophthalmology, Seoul Veterans Hospital, Seoul, Korea Purpose: To evaluate the clinical efficacy and complications of intraocular lens (IOL) exchange. Methods: A review of medical records was performed for 52 eyes that had undergone an IOL exchange due to IOL opacification. Surgical complications and their incidences were analyzed. The mean best corrected visual acuity (BCVA) after the IOL exchange was compared with the mean pre-exchange BCVA and with the mean BCVA after the initial IOL implantation. Prediction error of refraction and biometric data obtained for the IOL exchange were, if available, compared with those obtained for the initial IOL implantation. The prediction error for the IOL exchange, calculated from the biometric data obtained before the IOL exchange, was compared with that calculated from the measurements obtained before the initial IOL implantation. Results: The overall complication rates were low and no serious complications were found. The mean BCVA improved significantly after the IOL exchange and was not significantly different from that obtained after the initial IOL implantation. However, the refractive prediction for the IOL exchange was not as good as it was for the initial IOL implantation, which was thought to be related with difficulties in axial length (AL) measurements. Biometric data taken before the initial IOL implantation was associated with a significantly better refractive prediction than those taken before the IOL exchange. Conclusions: IOL exchange was both efficacious and safe for visual recovery. However, IOL exchange was related with increased difficulty of predicting postoperative refraction; difficulties in AL measurements are the suggested cause. Korean J Ophthalmol 2008;22:228-235 ⓒ 2008 by the Korean Ophthalmological Society. Key Words: Axial length measurement, Intraocular lens exchange, Intraocular lens implantation, Intraocular lens opacification, Prediction error of refraction Implantation of a foldable intraocular lens (IOL) takes an essential part of modern cataract surgery. Since SI-18NB (AMO ® , USA) was used as the first foldable IOL,1 there have been many changes made in IOL shape and composition to improve surgical outcomes and to minimize complications. Despite the remarkable improvements in the currently used IOLs, there have been discouraging clinical reports regarding unexpected late opacification of the implanted IOLs which is of concern to both patients and surgeons. Delayed opacification of foldable hydrophilic acrylic IOLs is a well-known phenomenon. Pathological studies using light microscopy, scanning electron microscopy, and X-ray spectroscopy have revealed that the opacification was caused by granular deposits composed of calcium phosphate hydroxide (hydroxyapatite) under the surface of the IOL.2-4 Neodymium:YAG (Nd:YAG) laser treatment was used to Received: June 5, 2008 Accepted: November 2, 2008 Reprint requests to Sangkyung Choi, MD. Department of Ophthal- mology Seoul Veterans Hospital, Dunchon2-dong, Gangdong-gu, Seoul 134-791, Korea. Tel: 82-2-2225-1382, Fax: 82-2-2225-1485, E-mail: drskchoi@hanmail.net 228 manage this complication by some authors.5 Although the authors attempted to blast the deposits from the IOL with laser treatment, the results were disappointing. Nd:YAG laser treatment did not remove the deposits or improve vision. Meanwhile, several studies have reported that an IOL exchange improves vision in such cases.5-8 In addition to IOL opacification, there are several circumstances under which explantation of an IOL, with or without implantation of a new IOL, is required as the definitive treatment. These circumstances include implantation of an IOL with incorrect power, an IOL defect, abnormal IOL position, glare symptoms, uveitis glaucoma hyphema (UGH) syndrome, and chronic uveitis.9-11 However, it seems that the indications for an IOL exchange are not limited to the management of these complicated cases, but may also include those patients requiring refractive changes. There are already several reports regarding IOL exchange procedures performed for patients favoring monovision in whom the initial IOL implantation surgeries resulted in similar refractive outcome in both eyes and for those who experienced unexpected hyperopic or myopic surprises.9,12 With further popularization of multifocal IOLs, it seems that