What do we really know about the effectiveness of glaucoma interventions: An overview of systematic reviews

OBJECTIVE: To identify systematic reviews on interventions for glaucoma conditions and assess their reliability, thereby generating a list of potentially reliable reviews for updating the glaucoma practice guidelines.DESIGN: Cross sectional study PARTICIPANTS: Systematic reviews of interventions for glaucoma conditions.METHODS: We used a database of systematic reviews and meta-analyses in vision research and eye care maintained by the Cochrane Eyes and Vision United State Satellite as a source of reviews. We examined all Cochrane systematic reviews of interventions for glaucoma conditions published before August 7th, 2019 and all non-Cochrane systematic reviews of interventions for glaucoma conditions published between January 1st, 2014 and August 7th, 2019.MAIN OUTCOME MEASURES: We assessed eligible reviews for reliability, extracted characteristics, and summarized key findings from reviews classified as reliable.RESULTS: Of the 4,451 systematic reviews in eyes and vision identified, 129 met our eligibility criteria and were assessed for reliability. Of these, we classified 49 (38%) as reliable. We found open-angle glaucoma (22/49) to be the condition with the most reviews and medical management (17/49) and intraocular pressure (43/49) to be the most common interventions and outcomes studied. Most reviews found a high degree of uncertainty in the evidence, which hinder the possibility of making strong recommendations in guidelines. These reviews found high-certainty evidence about a few topics: reducing IOP helps prevent glaucoma and its progression; prostaglandin analogues are the most effective medical treatment for lowering IOP; laser trabeculoplasty is as effective as medical treatment as a first-line therapy in controlling IOP; the use of IOP lowering medications peri- or post-operatively to accompany laser (e.g., trabeculoplasty) reduces the risk of post-operative IOP spikes; conventional surgery (i.e., trabeculectomy) are more efficacious than medications in reducing IOP; antimetabolites and beta-radiation improve IOP control after trabeculectomy. There is weak evidence regarding the effectiveness of minimally invasive glaucoma surgeries.CONCLUSIONS: The majority of systematic reviews evaluating interventions for glaucoma are of poor reliability. Even among those that may be considered reliable, there are important limitations in the value of information due to the uncertainty of the evidence as well as small and sometimes unimportant clinical differences between interventions.