Deposits on the optical surfaces of hydroview intraocular lenses

Abstract

The Bausch & Lomb Surgical Hydroview™ intraocular lens (IOL) is a foldable hydrogel posterior chamber design that has been implanted for several years in international markets; approximately 417 000 have been sold worldwide. However, although it was cleared for marketing in November 1999 by the Food and Drug Administration (FDA), it has not yet been launched for general implantation in the United States. In our opinion, this lens has many attractive features, including the single-piece nature, the C-haptic configuration, the good haptic material (poly[methyl methacrylate]), a hydrophilic optic material that can be advantageous in some clinical situations, and the ability to appropriately fold. However, late postoperative crystalline deposit formation on the surfaces of Hydroview lenses causing haze/opacification has recently been reported. As of March 2000, Bausch & Lomb Surgical has announced 76 cases in 9 centers worldwide, with more than two-thirds of cases (71%) occurring in 3 centers (Hong Kong, Canada, and Sweden). Seventeen lenses have been explanted because the haze/opacification was significant enough to affect visual function. No associated signs of ocular inflammation were reported. The deposits were generally observed 1 year after implantation. Some attempts to clean the lens surfaces with a neodymium:YAG laser were made but without success. We now know that at least some of the deposits consist of calcium. Five of the explanted lenses (5 halves) were sent to our Center for Research on Ocular Therapeutics and Biodevices for evaluation. Staining with a special stain, alizarin red, revealed the deposits to be composed of calcium in all 5 cases (Figure 1). 1 Scanning electron microscopic and energy dispersive x-ray analyses performed on the other halves of the same 5 lenses at Bausch & Lomb Laboratories revealed the deposits to be composed of calcium and phosphates (George Green, PhD, personal communication, February 2000).Figure 1.: (Apple) Photomicrograph of a Hydroview lens explanted 17 months after cataract surgery. Two parallel clear lines on the optic demarcate the axis of lens folding. The optical surface is almost completely covered by granular deposits; these stain positively for calcium with the alizarin red stain (alizarin red; original magnification ×40).In addition, Dr. Crayford from Orange, Australia, performed infrared spectroscopic analyses on other explanted lenses that revealed the presence of the same components (Basil B. Crayford, FRACO, personal communication, February 2000). This was confirmed by Raman spectra analysis performed by Dr. A.K.F. Yu in Hong Kong (A.K.F. Yu, et al., “Pathological and Chemical Analysis of Hydrogel Intraocular Lens Opacified in Vivo,” presented at the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida, USA, May 2000). These analyses also demonstrated that the depositions were superficial and did not involve the internal polymer structure of the lenses. In February 2000, the manufacturer sent a letter to all Hydroview users, informing them of the calcification on the lens surfaces, to find out whether other centers have experienced the condition. One month after the dissemination of this letter, new cases were reported, essentially from the same centers. It should be noted that other European centers have had a positive experience with Hydroview; for example, Dr. Voudouri in Greece in a 2 year follow-up study of 1200 lenses with no known evidence of calcification (A. Voudouri, MD, “Retrospective Study of the Hydrogel [Bausch & Lomb, H60M, Hydroview] Foldable Intraocular Lens,” presented at the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida, USA, May 2000). No cases of calcification have been reported in the U.S. clinical trial centers. Our laboratory, ophthalmologists overseas who are implanting the Hydroview lens, researchers from different universities, and the manufacturer are making efforts to identify the possible causes of this phenomenon. Factors that have been investigated include the IOL packaging, intraocular solutions and viscoelastic agents used during the surgical procedure, local surgical techniques, and pre-existing conditions in the affected patients. It is important that we continue to analyze outcomes to determine whether the calcification phenomenon is a local, sporadic finding occurring in some centers or a widespread one that may warrant a second look at the lens. As information becomes available, we will disseminate timely recommendations to surgeons. Our center and laboratory have no financial interest in this product or manufacturer. Funding for our studies is obtained with nonrestricted donations from multiple pharmaceutical and IOL companies, foundations, and private sources. David J. Apple MD Liliana Werner MD, PhD Marcela Escobar-Gomez MD Suresh K. Pandey MD aCharleston, South Carolina, USA