Aqueous shunts for glaucoma

Background Aqueous shunts are employed to control intraocular pressure (IOP) for people with primary or secondary glaucomas who fail or are not candidates for standard surgery. Objectives To assess the effectiveness and safety of aqueous shunts for reducing IOP in glaucoma compared with standard surgery, another type of aqueous shunt, or modification to the aqueous shunt procedure. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 8), MEDLINE Ovid (1946 to August 2016), Embase.com (1947 to August 2016), PubMed (1948 to August 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to August 2016), ClinicalTrials.gov (www.clinicaltrials.gov); searched 15 August 2016, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 15 August 2016. We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 15 August 2016. We also searched the reference lists of identified trial reports and the Science Citation Index to find additional trials. Selection criteria We included randomized controlled trials that compared various types of aqueous shunts with standard surgery or to each other in eyes with glaucoma. Data collection and analysis Two review authors independently screened search results for eligibility, assessed the risk of bias, and extracted data from included trials. We contacted trial investigators when data were unclear or not reported. We graded the certainty of the evidence using the GRADE approach. We followed standard methods as recommended by Cochrane. Main results We included 27 trials with a total of 2099 participants with mixed diagnoses and comparisons of interventions. Seventeen studies reported adequate methods of randomization, and seven reported adequate allocation concealment. Data collection and follow‐up times varied. Four trials compared an aqueous shunt (Ahmed or Baerveldt) with trabeculectomy, of which three reported one‐year outcomes. At one‐year, the difference in IOP between aqueous shunt groups and trabeculectomy groups was uncertain (mean difference (MD) 2.55 mmHg, 95% confidence interval (CI) ‐0.78 to 5.87; 380 participants; very low‐certainty evidence). The difference in logMAR visual acuity was also uncertain (MD 0.12 units, 95% CI ‐0.07 to 0.31; 380 participants; very low‐certainty evidence).