Trabeculectomy for neovascular glaucoma in proliferative diabetic retinopathy, central retinal vein occlusion, and ocular ischemic syndrome: Surgical outcomes and prognostic factors for failure

PURPOSE: To evaluate the outcomes of trabeculectomy in the eyes with neovascular glaucoma (NVG), caused by proliferative diabetic retinopathy (PDR), central retinal vein occlusion (CRVO), and ocular ischemic syndrome (OIS). METHODS: A retrospective review of NVG eyes that underwent trabeculectomy between 1991 and 2019. Complete success was defined as intraocular pressure (IOP) between 6 and 21 mmHg without antiglaucoma medications (AGM). The risk factors were analyzed by Cox's proportional hazard model. RESULTS: The study included 100 eyes of 100 subjects with a mean age of 58 ± 9.8 years and a median follow-up of 1.27 years (interquartile range: 0.63, 2.27). The cause of NVG was PDR in 59 eyes (59%), CRVO in 25 eyes (25%), and OIS in 16 eyes (16%). Trabeculectomy with mitomycin-C was performed in 88 eyes and trabeculectomy in 12 eyes. The cumulative complete success probability of trabeculectomy in PDR was 50% (95% confidence interval [CI]: 38, 65) at 1 year, 8% (1, 46) at 3–5 years. In OIS, it was 64% (43, 96) from 1 to 5 years. In CRVO, it was 75% (59, 94) at 1 year, 45% (23, 86) from 2 to 5 years. The PDR was associated with a higher risk of surgical failure compared to OIS (P = 0.04) and CRVO (P = 0.004). Other significant risk factors were increasing age (P = 0.02), persistent neovascularization of iris (NVI) (P = 0.03), higher number of anti-vascular endothelial growth factor (VEGF) injections prior to trabeculectomy (P = 0.02), and delay in performing trabeculectomy (P = 0.02). CONCLUSION: Compared to CRVO and OIS, the eyes with NVG secondary to PDR had poor success with trabeculectomy. Older age, persistent NVI, need for a higher number of anti-VEGF injections, and delayed surgery were associated with a higher risk for trabeculectomy failure.