Surgical treatment of neovascular glaucoma: a systematic review and meta-analysis.

Purpose: This literature review and meta-analysis aims to compare intraocular pressure (IOP) lowering efficacy, failure rates and loss of light perception (LP) rates 6 months after an IOP-lowering surgical procedure in neovascular glaucoma (NVG) eyes.
Methods: MEDLINE and EMBASE were used as data sources. Only studies including NVG patients who underwent two different surgical approaches were considered. The treatment effect measures were (i) weighted mean difference (WMD) for IOP reduction, (ii) risk ratio (RR) for failure rates and (iii) risk difference (RD) for loss of LP. Outcome measures were reported with a 95% confidence interval (CI) and P < 0.05 was considered statistically significant. Analysis was performed using RevMan v5.0.
Results: No RCT were retrieved. Seven comparative non-randomised studies were eligible. In glaucoma drainage devices (GDDs) vs cyclophotocoagulation arm, there was no statistical difference in IOP-lowering efficacy (WMD = - 3.63; CI [- 8.69, 1.43], P = 0.16), although failure rates and loss of LP were lower in the GDDs group (RR = 0.64, CI [0.41, 0.99], P = 0.05; and RD = - 0.15, CI [- 0.25, - 0.05], P = 0.004, respectively). In the Ahmed glaucoma valve (AGV) vs trabeculectomy arm, there was no statistical difference in IOP-lowering efficacy and loss of LP (WMD = 0.78, CI [- 2.29, 3.85], P = 0.62 and RD of 0.04, CI [- 0.05, 0.14], P = 0.34, respectively), but failure rates were lower in trabeculectomy group (RR of 2.25, CI [1.14, 3.71], P = 0.02).
Conclusions: There is lack of high-quality evidence on the subject as no RCT were retrieved comparing two different IOP-lowering procedures in NVG patients. Our findings are based, therefore, on non-RCT studies and should be interpreted with caution. There appears to be no difference in IOP-lowering efficacy between GDDs and cyclophotocoagulation, although GDDs appear to be safer. AGV and trabeculectomy also seem to provide similar IOP-lowering results with trabeculectomy showing lower failure rates.