THE ARTIFICIAL IRIS DIAPHRAGM FOR VITREORETINAL SILICONE OIL SURGERY

Background: 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'' a rtificial 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 bec ame necessary. The ''closed'' artificial diaphragm was developed. Meth ods: 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 h ypotonic as a result of injury, proliferative vitreoretinopathy, proli ferative diabetic retinopathy, or uveitis, with an intact natural iris diaphragm. Results: Silicone oil was retained behind the open diaphra gm throughout the observation period in 40% of the eyes. Major long-te rm complications were hypotony and fibrous overgrowth. Silicone was re tained behind the closed diaphragm in 50% of the eyes. Conclusion: Bec ause proliferative vitreoretinopathy is active for months and multiple surgical interventions become necessary to avoid phthisis in eyes wit h highly pathologic changes, longstanding or permanent silicone tampon ade is used, The artificial diaphragm prevents silicone-corneal contac t in approximately 50% of aphakic eyes for at least 1 year.