[Experience with the artificial iris diaphragm in hypotonic eyes]

As a result of a partial or complete loss of the natural iris diaphragm,longstanding silicone oil tamponade frequently causes keratopathy. An artificial iris diaphragm can avoid such a complication. In hypotony, with insufficient circulation of aqueous humor, the "closed" artificial iris diaphragm is used.

In this retrospective study 41 patients (41 eyes) were reviewed. Each patient had a single aphakic eye, in which a closed iris diaphragm was implanted after silicone oil surgery. The underlying diagnosis included in these 41 cases included trauma (22 eyes, 54%), retinal detachment due to proliferative vitreoretinopathy (12 eyes, 29%), severe uveitis (4 eyes, 10%), and proliferative diabetic retinopathy (3 eyes, 7%). The mean follow-up time was 12 month.

In 25 eyes (61%) silicone oil was retained behind the diaphragm. In 14 eyes (34%), silicone oil prolapsed in the anterior chamber. In 2 eyes (5%) the silicone oil could not been assessed due to a corneal opacity.A deteriorated corneal situation after implantation of the diaphragm was observed in 11 eyes (27%). As a longstanding complication permanent hypotony (< or = 5 mmHg) developed in 29 eyes (71%), fibrous reaction in 13 eyes (32%) within fibrotic membranes (9 eyes, 22%). The visual acuity remained stable in 39 eyes (95%), improved in none, and deteriorated in 2 eyes (5%).

Despite all complications, the artificial iris diaphragm represents an important progress in the salvage of severely traumatized eyes though persistent hypotony remains in 29 eyes (71%). Contact of silicone oil with the endothelium was avoided in 25 eyes (61%). There was no phthisis bulbi or enucleation. Improvement of anterior-posterior separation is necessary.