Late optic calcification in hydrophilic acrylic lens poses vision risks

Dr. Haymore, who was an ophthalmic pathology fellow at John A. Moran Eye Center, University of Utah Health Sciences Center, Salt Lake City, reported on eight cases of misdiagnosis of MemoryLens IOL calcification, of which three developed serious complications.

The MemoryLens is a three-piece hydrophilic acrylic IOL that offers high biocompatibility and material flexibility that make it useful for modern small-incision cataract surgery. However, it has been associated with a number of reports of postoperative opacification associated with calcium deposition on the lens surface as well as within the optic of some implants.

The eight cases of calcification that were reviewed by Dr. Haymore, in collaboration with Liliana Werner, MD, PhD, Nick Mamalis, MD, and Gerald Zaidman, MD, among others, involved patients from four centers nationwide. All had received the MemoryLens between late 1999 and the spring of 2000.

"Pay attention to the date of implantation because that can be a useful clue to the cause of the visual problem," Dr. Haymore said.

Development of small, punctate opacifications and complaints of decreased visual function occurred between 13 and 58 months after implantation. The average time to detection of opacification was 39 months.

Four eyes were misdiagnosed as having posterior capsule opacification and underwent Nd:YAG laser capsulotomy. The other four eyes were thought to have some vitreous abnormality and underwent vitrectomy.

Postoperative complications

Six of the eight eyes eventually underwent IOL exchange when IOL opacification was recognized. Three of those six eyes developed postoperative complications that included recurrent cystoid macular edema, retinal detachment or choroidal hemorrhage, and coagulase-negative staphylococcal endophthalmitis with phthisis.

Two of the explanted IOLs were available for further analysis at the John A. Moran Eye Center, University of Utah, Salt Lake City. Light and scanning electron microscopy demonstrated fine granularity on the anterior and posterior IOL optic surfaces. Energy dispersive x-ray spectroscopy demonstrated the presence of calcium and phosphate spikes from the surface granules. Slit-lamp photos of the calcified MemoryLens IOLs also highlighted the presence of fine granularity of the optic surfaces.

"If MemoryLens opacification is suspected, perform a careful slit-lamp exam paying special attention to the IOL optic surfaces for signs of granularity or opacification," said Dr. Haymore.