What Do We Really Know about the Effectiveness of Glaucoma Interventions?: An Overview of Systematic Reviews.

PURPOSE

To identify systematic reviews of interventions for glaucoma conditions and to assess their reliability, thereby generating a list of potentially reliable reviews for updating 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 States Satellite. We examined all Cochrane systematic reviews of interventions for glaucoma conditions published before August 7, 2019, and all non-Cochrane systematic reviews of interventions for glaucoma conditions published between January 1, 2014, and August 7, 2019.

MAIN OUTCOME MEASURES

We assessed eligible reviews for reliability, extracted characteristics, and summarized key findings from reviews classified as reliable.

RESULTS

Of the 4451 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 (IOP; 43/49) to be the most common interventions and outcomes studied. Most reviews found a high degree of uncertainty in the evidence, which hinders the possibility of making strong recommendations in guidelines. These reviews found high-certainty evidence about a few topics: reducing IOP helps to prevent glaucoma and its progression, prostaglandin analogs 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 in the perioperative or postoperative periods to accompany laser (e.g., trabeculoplasty) reduces the risk of postoperative IOP spikes, conventional surgery (i.e., trabeculectomy) is more effective than medications in reducing IOP, and antimetabolites and β-radiation improve IOP control after trabeculectomy. The evidence is weak regarding the effectiveness of minimally invasive glaucoma surgeries.

CONCLUSIONS

Most systematic reviews evaluating interventions for glaucoma are of poor reliability. Even among those that may be considered reliable, important limitations exist in the value of information because of the uncertainty of the evidence as well as small and sometimes unimportant clinical differences between interventions.