Surgical Treatment of Neovascular Glaucoma Secondary to Proliferative Diabetic Retinopathy in Japanese Patients without the Use of Glaucoma Drainage Devices

Abstract

Purpose: The purpose of this study is to investigate outcomes of visual acuity (VA) and intraocular pressure (IOP) in proliferative diabetic retinopathy (PDR)-associated neovascular glaucoma (NVG) in Japanese patients treated with surgical therapies without the use of glaucoma drainage devices. Methods: A retrospective analysis of medical records was conducted for 31 consecutive PDR-associated NVG patients who underwent surgical treatments in our institution between 2013 and 2022. Patient demographics, clinical characteristics, VA, and IOP were recorded at the first and last visits, and surgical procedures, including pars plana vitrectomy with extensive panretinal and ciliary photocoagulation (PPV–PRCP), diode laser trans-scleral cyclophotocoagulation (DCPC), and trabeculectomy with mitomycin C (TLE–MMC), with or without a prior intravitreal bevacizumab (IVB) injection, were reviewed. Results: Of the thirty-one PDR patients with NVG, two patients received PPV–PRCP or DCPC alone (6.5%), respectively, three patients received TLE–MMC alone (9.7%), two patients received TLE–MMC after IVB (6.5%), six patients received PPV–PRCP and TLE–MMC (19.4%), seven patients received PPV–PRCP and TLE–MMC after IVB (22.6%), five patients received PPV–PRCP and DCPC and TLE–MMC (16.1%), and four patients received PPV–PRCP and DCPC and TLE–MMC after IVB (12.9%). The VA of two patients (6.5%) deteriorated to no light perception. In all patients, the mean logMAR VA was 1.28 ± 1.05 at the first visit and remained at 1.26 ± 1.08 at the last visit, with no significant change; the mean IOP was 33.0 ± 15.2 mmHg at the initial visit and decreased significantly to 14.0 ± 7.4 mmHg at the last visit. The number of eyes with IOP ≥ 21 decreased from twenty-eight (90.3%) to three (9.7%). Although IOP in patients with IOP > 30 mmHg at the initial visit reduced to a level comparable to that of patients with IOP ≤ 30 mmHg, the IOP > 30 mmHg group received IVB more frequently and had significantly higher logMAR VA at the last visit compared to the IOP ≤ 30 mmHg group. Hypotony (<6 mmHg) was observed in four eyes (12.9%). Conclusions: In PDR patients with NVG, various combinations of PPV–PRCP, DCPC, and TLE–MMC after adjunctive IVB without the use of glaucoma drainage devices lowered IOP sufficiently; for these patients, neovascular regression was observed, with no further deterioration of VA. However, surgical procedures should be performed for PDR patients with NVG before visual impairment occurs. On the other hand, approximately less than 15% of patients developed blindness or low IOP.