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Original Investigation
July 15, 2021

Minimally Invasive Glaucoma Surgical Techniques for Open-Angle Glaucoma: An Overview of Cochrane Systematic Reviews and Network Meta-analysis

Author Affiliations
  • 1Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor
  • 2Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
  • 3Centre for Public Health, Queen’s University, Belfast, United Kingdom
  • 4Glaucoma Service, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
  • 5Institute of Ophthalmology UCL & NIHR Biomedical Research Centre, London, United Kingdom
  • 6Cochrane Eyes and Vision, ICEH, London School of Hygiene & Tropical Medicine, London, United Kingdom
  • 7Research and Development Department & NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
  • 8The Royal Marsden NHS Foundation Trust, London & Surrey, United Kingdom
  • 9Department of Ophthalmology, Nottingham University Hospital, Nottingham, United Kingdom
  • 10Centro de la Visión, Clínica las Condes, Santiago, Chile
  • 11Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora
JAMA Ophthalmol. Published online July 15, 2021. doi:10.1001/jamaophthalmol.2021.2351
Key Points

Question  What is the comparative effectiveness and safety of minimally invasive glaucoma surgeries?

Findings  This meta-analysis examined 6 Cochrane systematic reviews of randomized clinical trials that described 6- to 60-month outcomes of minimally invasive glaucoma surgeries. Compared with cataract surgery alone, addition of a trabecular bypass stent (Hydrus microstent or iStent) safely improved glaucoma control without use of medication and the Hydrus also conferred approximately 2.0-mm Hg intraocular pressure lowering; available data were insufficient to compare other minimally invasive glaucoma surgeries techniques.

Meaning  Among currently available minimally invasive glaucoma surgeries for which randomized clinical trial data have been published, Hydrus was associated with greater glaucoma control without medication and lowering of intraocular pressure than iStent, although effect sizes were small.


Importance  Glaucoma affects more than 75 million people worldwide. Intraocular pressure (IOP)–lowering surgery is an important treatment for this disease. Interest in reducing surgical morbidity has led to the introduction of minimally invasive glaucoma surgeries (MIGS). Understanding the comparative effectiveness and safety of MIGS is necessary for clinicians and patients.

Objective  To summarize data from randomized clinical trials of MIGS for open-angle glaucoma, which were evaluated in a suite of Cochrane reviews.

Data Sources  The Cochrane Database of Systematic Reviews including studies published before June 1, 2021.

Study Selection  Reviews of randomized clinical trials comparing MIGS with cataract extraction alone, other MIGS, traditional glaucoma surgery, laser trabeculoplasty, or medical therapy.

Data Extraction and Synthesis  Data were extracted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines by one investigator and confirmed by a second. Methodologic rigor was assessed using the AMSTAR 2 appraisal tool and random-effects network meta-analyses were conducted.

Main Outcomes and Measures  The proportion of participants who did not need to use medication to reduce intraocular pressure (IOP) postsurgery (drop-free). Outcomes were analyzed at short-term (<6 months), medium-term (6-18 months), and long-term (>18 months) follow-up.

Results  Six eligible Cochrane reviews were identified discussing trabecular bypass with iStent or Hydrus microstents, ab interno trabeculotomy with Trabectome, subconjunctival and supraciliary drainage devices, and endoscopic cyclophotocoagulation. Moderate certainty evidence indicated that adding a Hydrus safely improved the likelihood of drop-free glaucoma control at medium-term (relative risk [RR], 1.6; 95% CI, 1.4 to 1.8) and long-term (RR, 1.6; 95% CI, 1.4 to 1.9) follow-up and conferred 2.0-mm Hg (95% CI, −2.7 to −1.3 mm Hg) greater IOP reduction at long-term follow-up, compared with cataract surgery alone. Adding an iStent also safely improved drop-free disease control compared with cataract surgery alone (RR, 1.4; 95% CI, 1.2 to 1.6), but the short-term IOP-lowering effect of the iStent was not sustained. Addition of a CyPass microstent improved drop-free glaucoma control compared with cataract surgery alone (RR, 1.3; 95% CI, 1.1 to 1.5) but was associated with an increased risk of vraision loss. Network meta-analyses supported the direction and magnitude of these results.

Conclusions and Relevance  Based on data synthesized in Cochrane reviews, some MIGS may afford patients with glaucoma greater drop-free disease control than cataract surgery alone. Among the products currently available, randomized clinical trial data associate the Hydrus with greater drop-free glaucoma control and IOP lowering than the iStent; however, these effect sizes were small.

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