Outcome Comparisons for Neovascular Glaucoma Treated with either Trabeculectomy or Ahmed Valve Implantation

Abstract

Objective: To compare outcomes for the surgical management of neovascular glaucoma (NVG) by either trabeculectomy and mitomycin C (MMC) or Ahmed valve implantation. Methods: In this retrospective case series study, 29 eyes of 28 NVG patients were recruited from June 2009 to January 2013 at Department of Ophthalmology, the NO.2 People's Hospital of Changshu, were divided into two groups by treatment. Fourteen eyes of 13 patients in Group Ⅰ underwent pars plana vitrectomy (PPV) and panretinal photocoagulation (PRP) followed by trabeculectomy and MMC, while 15 eyes of 15 patients of Group Ⅱ underwent PPV and PRP combined with Ahmed valve implantation. Synechial closure of the anterior chamber angle, regression of iris neovascularization, best corrected visual acuity (BCVA), intraocular pressure (IOP), and surgical success rate were analyzed during 4 to 6 years of follow-up. The datas were analyzed with t-tests, Fisher's exact tests, and Mantel-Cox survival analysis. Results: There were no significant differences between the two groups after surgery in synechial closure of the chamber angle or regression of iris neovascularization. Visual acuity of all patients was preserved in the follow-up period, although postoperative BCVA in neither group improved significantly. There was no significant difference of preoperative or postoperative IOP between the two groups. The mean postoperative IOP for both groups at all follow-up times was significantly lower than the preoperative IOP (all P<0.001). There was no significant difference in the success rate between the two groups at 18 months after surgery. However, the success rate of Group II was significantly higher than that of Group I at the end of the follow-up period (χ2=5.093, P=0.024). Conclusions: The procedures of PPV and PRP combined with trabeculectomy with MMC or Ahmed valve implantation were practicable in the management of NVG. However, PPV and PRP combined with Ahmed valve implantation was more effective for the long term. Key words: neovascular glaucoma; pars plana vitrectomy; panretinal photocoagulation; trabeculectomy; Ahmed valve implantation