[Calcification on the posterior surface of an implanted silicone intraocular lens in a patient with asteroid hyalosis].

Background: Calcification on the surface of the hydrogel intraocular lens (IOL) has been reported, but the mechanism of the surface calcification is not fully understood. We report a case of surface calcification on an implanted silicone IOL. The purpose of our study was to examine the clinical and ultrastructural findings associated with the late surface calcification of a silicone IOL.

Case: A 70-year-old Japanese man had undergone cataract surgery in his left eye, with uneventful phacoemulsification and silicone IOL (Allergan SI-55 NB) implantation with the manufacturer's cartridge and injector. He was referred again 29 months later with blurred vision, glare sensitivity, and decreased vision in his left eye. He was diagnosed as having aftercataract. Although YAG laser capsulotomy was performed, the opacity on the posterior surface gradually increased. The opacity was located mainly within the capsulotomy window on the posterior surface of the lens, although the patient maintained good visual acuity. LV : 0.2 (1.0 x S-2.0 D). The lens was removed 46 months after the initial surgery. Scanning electron microscopy (SEM) showed membranous deposits on the posterior optical surface of the silicone lens. There were high levels of phosphoric acid (P) and calcium (C) confirming calcification of the silicone IOL. Asteroid hyalosis was observed in the fellow eye of the patient.

Conclusion: This is the first report of surface calcification of a silicone IOL in Japan. Although the mechanism of the calcification has not been determined, careful clinical follow-up of patients implanted with silicone lenses is necessary to determine if this phenomenon is rare and sporadic or if it may be more widespread. Since 5 similar cases of calcification in silicone lenses with accompanying asteroid hyalosis have been reported in other countries, we can conclude that silicone lens implantation in eyes with asteroid hyalosis should be avoided.