Factors influencing the results of vitreous surgery in diabetic retinopathy. I. Iris rubeosis and/or active neovascularization at the fundus.

A consecutive series of 100 vitrectomies for tractional retinal detachment involving the macula in proliferative diabetic retinopathy was analyzed to determine the influence of preoperative iris rubeosis (NVI) and active neovascularization at the fundus (NVF) on surgical results. The minimum follow-up was 12 months. Preoperatively, iris rubeosis was present in 52% and active neovascularization at the fundus in 85%. Surgery was performed under Spitznas wide-angle observation, using a stereoscopic diagonal inverter, either with the panfundoscope or binocular ophthalmoscopy through the operating microscope. Most of the eyes were phakic (94%). No lensectomy was performed. Anatomical success was achieved in 81%, ambulatory vision in 77%. Anatomical success was reduced to 63% in cases with preoperative NVI and to 78% in cases with preoperative NVF. Including 5 cases of re-vitrectomy, silicone oil was used for internal tamponade in 9%, SF 6/air 50:50 in 39% and air in 26%. In 26%, no internal tamponade was applied. Postoperative complications consisted of vitreous hemorrhage (25%), increased rubeosis (22%), neovascular glaucoma (2%), and redetachment (7%). The final causes of failure in 19% of eyes were: neovascular glaucoma (1%), rubeosis/hypotony/cataract (14%), and phthisis bulbi (4%).