Systematic literature review of clinical, economic, and humanistic outcomes following minimally invasive glaucoma surgery or selective laser trabeculoplasty for the treatment of open-angle glaucoma with or without cataract extraction

Author: Cantor L, Lindfield D, Ghinelli F, Swider AW, Torelli F, Steeds C, Dickerson JE, Nguyen DQ

Geographical coverage: Europe, North America, South America, Australia, Asia, Brazil, Canada, France, Germany, Italy, Japan, Mexico, Spain, the UK, and the USA.

Sector: Biomedical, Economic evaluation

Sub-sector: Treatment, quality of life, cost

Equity focus: Not explicitly stated

Study population: Adult patients with glaucoma

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background:

Primary open-angle glaucoma (OAG) is a progressive eye disease linked to high intraocular pressure (IOP), which can cause blindness. Keeping IOP below 18 millimetres of mercury (mmHg) can slow its progression. First-line treatments can delay or reduce OAG progression in patients with elevated IOP but may face adherence issues and side effects. Selective laser trabeculoplasty (SLT) and minimally invasive glaucoma surgery (MIGS) offer effective options for mild-to-moderate OAG. Recent studies on new devices highlight the need to update knowledge systematically.

Objectives:

To assess the clinical, economic, and humanistic outcomes of MIGS and SLT for the treatment of OAG.

Main findings:

The review included 81 publications, 74 primary publications and 7 secondary publications. The sample size in the included studies varied from 15 patients to 17,353 patients. Most studies were conducted in Europe (n=30), with the remainder conducted in North America (n=27), Australia (n=6), South America (n=4), and Asia (n=3).

A total of 58 publications reported clinical results, with the majority evaluating iStent or iStent inject (n=36), followed by OMNI (n=9). Across prospective studies, IOP reductions ranged from −31% to −13.7% at six months and from −39% to −15% at one year. Post-procedure IOP levels generally remained in the mid-teens, with greater reductions observed in patients with higher baseline IOP. Prospective studies demonstrated sustained effectiveness of MIGS and SLT, with IOP reductions varying based on device type, surgical approach (standalone or combined with cataract surgery), and patient population. OMNI achieved a mean absolute IOP reduction of 6.25 mmHg at 12 months when combined with cataract surgery. SLT showed an average 31% IOP reduction at six months and maintained effectiveness up to three years, with post-treatment IOP ranging from 14.4 mmHg for moderate OAG and 16.4 mmHg for mild OAG. Retrospective studies confirmed the effectiveness of SLT and MIGS in lowering IOP and reducing the use of IOP- lowering medications.

The review highlighted the humanistic and economic impact of mild-to-moderate OAG, emphasising its effects on quality of life (QoL) and healthcare costs. Nine primary studies reported humanistic outcomes for mild-to-moderate OAG population. Findings indicated that worsening glaucoma severity was linked to greater humanistic burden and reduced QoL. However, only two studies examined the humanistic impact of iStent/iStent inject, both reporting modest improvements in QoL.

Economic outcomes were reported in 15 studies conducted across Brazil, Canada, France, Germany, Italy, Japan, Mexico, Spain, the UK, and the USA. Studies (n=4) evaluating the direct costs of OAG treatment (medications, outpatient visits, hospitalisations) found that healthcare expenses increased with disease severity, with moderate glaucoma patients experiencing more hospitalisations and physician visits than those with mild disease. Laser therapy was identified as the most cost-effective option for mild glaucoma, while surgical interventions were more cost-effective for moderate-to-advanced cases. Additionally, several studies found overwhelming evidence supporting the cost-effectiveness of MIGS for mild-to-moderate OAG. However, indirect costs such as lost productivity and wage losses were not assessed, highlighting a gap in economic research.

Methodology:

Studies included at least 15 adults with mild-to-moderate OAG, featuring MIGS or SLT compared to other glaucoma treatments, and published in English between 2011 and 2021. Research from Australia, Brazil, Canada, China, France, Germany, Italy, Japan, Mexico, Poland, South Korea, Spain, Switzerland, the UK, and the USA was prioritised. Clinical outcomes were considered from RCTs and non-RCTs, including observational studies and real-world evidence. Studies reporting health‑related quality of life (HRQoL), patient burden, or economic outcomes in the target population were included.

The search was conducted in Medline, Embase, Cochrane Database, Cochrane Controlled Register of Trials, and ClinicalTrials.gov, and included additional sources up to January 2022. Two studies were found through grey literature. Articles were screened independently by two reviewers, with discrepancies resolved by a third.

Quality assessment used the Cochrane risk of bias-2 tool for RCTs, Newcastle-Ottawa scale for non-randomised studies, and the 24-item Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist for economic analyses. One reviewer assessed risk of bias, validated by a second reviewer. Data extraction was performed by one reviewer and validated by another, with findings synthesised narratively.

Applicability/external validity:

While the review did not explicitly discuss applicability or external validity, it highlighted geographic distribution, study designs, and population differences. Most studies were from the USA and Europe, with few from Asia, affecting generalizability. Methodological differences, including baseline IOP, study design, and outcome measures, may impact real-world applicability. The review calls for more real-world evidence and comparative studies to understand MIGS and SLT’s long-term effects in diverse populations.

Geographic focus:

Included studies were conducted in Europe, North America, South America, Australia, Asia, Brazil, Canada, France, Germany, Italy, Japan, Mexico, Spain, the UK, and the USA.

Summary of quality assessment:

Overall, we have medium confidence in the review’s conclusions because of methodological limitations: reference lists were not searched systematically, the search was restricted to English‑language publications, and risk‑of‑bias assessment was carried out by a single reviewer before validation by a second. These factors increase the likelihood that relevant evidence was missed and may introduce bias into the synthesis.