The artificial iris diaphragm for vitreoretinal silicone oil surgery

Silicone keratopathy frequently develops as a complication of silicone oil tamponade in the management of severe trauma in eyes with partial or complete aniridia. We therefore designed an "open" artificial iris diaphragm to prevent silicone oil-endothelial contact. In hypotony, where insufficient circulation of aqueous allows silicone in the anterior chamber despite an open diaphragm, a new solution became necessary. The "closed" artificial diaphragm was developed.

In this retrospective study, two consecutive series of artificial iris diaphragms were compared. Forty-four patients received either an open type (20 eyes) or a closed type (24 eyes) and were observed for 409 +/- 421 days (range, 32-1912). All eyes were aphakic, normotonous, and had a traumatic, compromised iris diaphragm or were aphakic and hypotonic as a result of injury, proliferative vitreoretinopathy, proliferative diabetic retinopathy, or uveitis, with an intact natural iris diaphragm.

Silicone oil was retained behind the open diaphragm throughout the observation period in 40% of the eyes. Major long-term complications were hypotony and fibrous overgrowth. Silicone was retained behind the closed diaphragm in 50% of the eyes.

Because proliferative vitreoretinopathy is active for months and multiple surgical interventions become necessary to avoid phthisis in eyes with highly pathologic changes, longstanding or permanent silicone tamponade is used. The artificial diaphragm prevents silicone-corneal contact in approximately 50% of aphakic eyes for at least 1 year.