Importance: To date, only a few studies have directly compared nonpenetrating surgery (NPS) and trabeculectomy (TE). Therefore, there is no strong evidence as to which surgical technique leads to the best results in terms of ocular hypotensive effect and safety.
Objective: To compare the hypotensive effect and safety of NPS and TE in terms of intraocular pressure (IOP) reduction and incidence of complications.
Data sources: The MEDLINE and EMBASE databases were searched for studies potentially eligible in any language published up to March 31, 2013.
Study selection: Systematic review and meta-analysis of comparative studies of 2 or more surgical techniques (1 of which had to be TE), including patients with open-angle glaucoma.
Data extraction and synthesis: The considered interventions were TE, deep sclerectomy (DS), viscocanalostomy, and canaloplasty.
Main outcomes and measures: The primary outcome was the mean between-group difference in the reduction in diurnal IOP from baseline to the 6- or 12-month follow-up evaluation. We also considered the incidence of complications, expressed as relative risk.
Results: Eighteen articles, accounting for 20 comparisons, were selected for data extraction and analysis. Analysis of the 6-month follow-up data showed that the pooled estimate of the mean between-group difference was -2.15 mm Hg (95% CI, -2.85 to -1.44) in favor of TE. There was no difference between the NPS subgroups. In the subgroup antimetabolite analysis, the addition of mitomycin C to TE and DS decreased the difference in the reduction in IOP (TE and DS without mitomycin C: -2.65 mm Hg [95% CI, -3.90 to -1.39]; TE and DS with mitomycin C: -0.83 mm Hg [95% CI, -2.40 to 0.74]). In the subgroup analysis by implant addition, no significant difference induced by DS with or without drainage devices was detected (test for subgroup differences: χ(2)(1) = 0.24; P = .62). The absolute risk of hypotony, choroidal effusion, cataract, and flat or shallow anterior chamber was higher in the TE group than in the NPS group.
Conclusions and relevance: Trabeculectomy seems to be the most effective surgical procedure for reducing IOP in patients with open-angle glaucoma. However, as expected, it was associated with a higher incidence of complications when compared with NPS.