INFLUENCE OF SILICONE OIL ON IRIS MICROANGIOPATHY IN DIABETIC VITRECTOMIZED EYES

Purpose: This study evaluates the influence of intraocular silicone oi l on iris diabetic microangiopathy in diabetic vitrectomized eyes. Met hods: The authors examined 20 eyes of 20 patients with diabetes underg oing primary vitrectomy for tractional diabetic retinal detachment, en dophotocoagulation, and 1000 centistokes silicone oil tamponade. The v ascular status of the iris in these eyes was examined by iris fluoresc ein angiography once before silicone oil injection and again when it w as removed (mean follow-up, 8.3 months). Results: Iris diabetic microa ngiopathy, including breakdown of the blood-iris barrier and iris neov ascularization, improved or remained stable in 40% of eyes. It worsene d in 60% bf eyes, including all aphakic eyes. Neovascular glaucoma dev eloped in one of them. A significant correlation was found between wor sening of iris diabetic microangiopathy and both aphakia (P = 0.01) an d severe immediate postvitrectomy inflammation (P = 0.02). Eyes with r ecurrent retinal detachment (n = 4) showed worsening of iris diabetic microangiopathy, but this was not significantly correlated. Conclusion : Aphakic vitrectomized eyes have a higher risk of iris diabetic micro angiopathy developing, even after silicone oil tamponade. Immediate po stoperative intraocular inflammation also is a risk factor for worseni ng of iris diabetic microangiopathy in phakic eyes. Recurrence of reti nal detachment was not significantly correlated with worsening of iris status.