Eyeworld

MAR 2013

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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66 EW CATARACT March 2013 Cataract/IOL complications: Moran CPC reports A case of late postoperative opacification of a PMMA IOL by Erica T. Liu, M.D., Liliana Werner, M.D., Ph.D., Nick Mamalis, M.D. A lthough clinicopathological correlation has always been fundamental to medicine, it was the late David Apple, M.D., who established the importance of this approach to modern cataract surgery and to the analysis of IOL safety and complications. Under the leadership of Dr. Apple and his department chair Randy Olson, M.D., the Center for IOL Research was established at the Moran Eye Center at the University of Utah in 1980. Since then, the steady stream of groundbreaking research from this leading academic center has taught us much about preventing IOL and capsular complications through lens design, IOL fixation, and surgical technique. As former Apple fellows (the so-called Apple Korps), Nick Mamalis, M.D., and Liliana Werner, M.D., have continued this important work at the Moran Eye Center, first as collaborators and now as successors to Dr. Apple. In the area of IOL and capsular complications, their academic productivity is unrivalled. Indeed, in recognition of these contributions, Nick will present the Binkhorst Medal Lecture at the ASCRS•ASOA Symposium & Congress in April. Although the peer-reviewed literature is filled with studies and publications from the Moran Eye Center, I believe that many of the lessons are best taught with a casebased approach. For this reason, I've asked Nick and Liliana to lead a regular EyeWorld column in which they will present a series of cataract/IOL CPC cases for our readers. David F. Chang, M.D., chief medical editor Erica T. Liu, M.D. W e are very pleased to contribute to EyeWorld with this column that will describe some of the cases analyzed in our laboratory at the Moran Eye Center. In this first article, we chose a case that illustrates a condition that may be observed with relatively older polymethyl methacrylate (PMMA) IOLs. We still receive many lenses in our laboratory that were explanted because of this particular problem and believe surgeons should be aware of this possibility. Case report A 53-year-old female with a history of bilateral cataract surgery and PMMA IOL implantation in 1985 presented with glare and blurred vision of her left eye as well as a "mottling" of her IOL. The patient was negative for a history of eye injury, hypertension, and diabetes. Best corrected visual acuity on presentation was 20/20 in the right eye and 20/20-1 in the left eye. Intraocular pressure by Tonopen was 21 mm Hg bilaterally. Dilated slit lamp exam showed an intact posterior capsule in the right eye and opacification of the IOL optic bilaterally. The intensity of the optic opacification was greater in the left eye. The remainder of the ocular exam was unremarkable. Progression of optic opacification and decrease in visual acuity were documented in the left eye, leading to explantation/exchange of the left IOL (Figure 1). Nick Mamalis, M.D. vealed a three-piece, posterior chamber rigid IOL manufactured from PMMA, with blue-colored haptics that were consistent with Prolene material (Figure 2). The optic contained four positioning holes, and the lens was explanted in toto without apparent damage. The presence of the four positioning holes provides a good indication that the lens was made of PMMA, as modern foldable lenses generally do not exhibit this feature. The optic exhibited a white discoloration located within the central 3 mm. Microscopic examination of the specimen showed that the central optic opacity was caused by the presence of multiple lesions with a morphological aspect of "snowflakes" (Figure 2). These were distributed within the optic substance of the Liliana Werner, M.D., Ph.D. lens at different depths, but especially close to the anterior optic surface. Comments The condition described in the case presented here was named snowflake degeneration due to the morphological aspect of the individual optic lesions under high magnification light microscopy. Snowflake degeneration is a slowly progressive opacification of PMMA lenses, at times, occurring 10 years or more after implantation. Snowflake degeneration has been observed in three-piece PMMA lenses implanted between the early 1980s and the mid 1990s, which were generally manufactured by injection molding. It has been hypothesized that this continued on page 68 Laboratorial analyses and results The specimen (explanted PMMA IOL) was submitted to our laboratory inside a contact lens case in the dry state. Gross examination re- Figure 1: Surgical view of the opacified PMMA lens, under pupil dilation Source: David F. Chang, M.D.

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