Foldable intraocular lens removal/exchange: Can it be prevented?

Abstract

One of the biggest disappointments and frustrations we face as ophthalmic surgeons is to encounter a patient who, after “successful” cataract surgery with intraocular lens (IOL) implantation, requires IOL removal with or without exchange. Generally, the factors responsible for explantation or exchange of an IOL can be broken down into 2 broad categories: factors related to the IOL design/material, or factors related to surgeon error (or a combination of both). Before the era of foldable IOLs, the predominant indications for IOL removal/exchange were very much different than they are today. When rigid all polymethyl methacrylate (PMMA) anterior chamber IOLs and singleand multipiece PMMA posterior chamber IOLs were most popular, the most common etiologies of IOL explantation/exchange included iritis, the uveitis/glaucoma/hyphema syndrome, cystoid macular edema (CME), corneal edema/bullous keratopathy, and damage to the IOL. Although these complications still lead to IOL explantation/exchange today, their frequency is much lower. This is in large part due to improved techniques and instrumentation in cataract extraction and changes in IOL design and materials. The use of foldable IOLs that are implanted after phacoemulsification through a small, usually clear corneal incision continues to increase. Foldable IOLs continue to evolve, with new lens materials and designs being introduced each year. Currently, the use of foldable IOLs predominates, with 95% of lenses implanted consisting of a foldable material. With this increase in foldable IOL use, however, has come a coincident increase in foldable IOL complications that require foldable IOL removal/exchange. As a consequence, the most frequent etiologies for explantation of this class of lenses differ from those of its predecessors (i.e., nonfoldable PMMA IOLs). In this issue, Neuhann et al remind us of this and describe the characteristics of a particularly unique complication leading to explantation of a specific class of IOLs. Reports such as this one that identify etiologies of IOL removal and the possible correlations linking these etiologies to specific IOL designs and/or materials will benefit us in our quest to minimize foldable IOL explantations/exchanges. Foldable materials available for use currently in the United States include silicone, acrylic (hydrophobic), hydrogel (hydrophilic acrylic), and collamer. Foldable IOL designs available for use currently in the United States include single-piece, plate-type lenses, single-piece lenses with haptics, 3-piece lenses, and multifocal lenses. Recently, Mamalis et al reported on their 2003 American Society of Cataract and Refractive Surgery/European Society of Cataract and Refractive Surgery survey of foldable IOLs requiring explantation or secondary intervention. The 3 most common etiologies for foldable IOL explantation or secondary surgical intervention were (in order of frequency): dislocation/decentration, incorrect lens power, and