Understanding Glaucoma Stent Cost-Effectiveness
Someone preparing for cataract surgery may also have glaucoma, a condition that damages the optic nerve and can gradually reduce vision. When both conditions need attention, an eye specialist may discuss whether adding a tiny drainage implant could help control eye pressure and reduce the need for medication.
But how much value does this additional procedure provide over time? A systematic review published in Cost Effectiveness and Resource Allocation in 2026 examined the economic evidence for combining an iStent-family trabecular micro-bypass device with cataract surgery in adults with mild-to-moderate open-angle glaucoma.
The review found that all eight included economic evaluations projected favorable cost-effectiveness in their primary analyses. However, these were model-based estimates rather than proof that every patient will experience long-term savings or better outcomes in routine clinical care.
What the Review Examined
Published online through Bioengineer.org on October 29, 2026, the report summarized a systematic review by Drobin, published in the journal Cost Effectiveness and Resource Allocation. The underlying review examined whether adding an iStent-family device to planned cataract surgery could provide sufficient health benefits to justify its additional cost.
The reviewer searched PubMed, Embase, the Cochrane Library, and Web of Science on July 27, 2026. The search identified 418 records, and eight economic evaluations from eight countries met the eligibility criteria after duplicates and ineligible records were removed.
Every included evaluation compared cataract surgery combined with an iStent device against cataract surgery alone. Seven studies used cohort Markov models, while one used an individual-patient Monte Carlo microsimulation involving 500,000 simulated patients.
These methods estimate how health, treatment costs, and outcomes may change over time. They can help decision-makers compare treatment options, but their conclusions depend on the assumptions and clinical evidence used to construct each model.
The review followed PRISMA 2020 reporting guidance and assessed the included evaluations using the CHEERS 2022 checklist. Its findings specifically concern adults with mild-to-moderate open-angle glaucoma who were already scheduled for cataract surgery, not every type of glaucoma or every use of a stent.
What the Cost-Effectiveness Results Showed
All eight evaluations reported favorable results in their base-case analyses, although the estimated costs and benefits differed between countries. For example, the reported incremental cost-effectiveness ratios included €1,154 per quality-adjusted life year in France, €12,676 in Spain, and €13,037 in Italy.
Other estimates included JPY 1,430,647 in Japan and A$2,430 in Australia. The Australian model estimated an additional cost of A$177 alongside a gain of 0.0726 quality-adjusted life years.
Two studies reported that the combined procedure was both less costly and more effective than cataract surgery alone. A Canadian analysis reported a ratio of −CAD 16,691 and a 73.7% probability of cost savings, while a United States analysis estimated costs were USD 4,809.39 lower and outcomes improved by 0.17 quality-adjusted life years.
A quality-adjusted life year, or QALY, combines length of life and health-related quality of life into a single measure. An incremental cost-effectiveness ratio compares the additional cost of an intervention with the additional health benefit it is expected to provide.
These figures should not be treated as directly interchangeable. Healthcare prices, reimbursement arrangements, economic assumptions, and accepted cost-effectiveness thresholds differ between countries, meaning a result considered favorable in one setting may not translate to another.
Why Time Horizon and Disease Severity Matter
A central finding was that the time period used in an economic model can change its conclusions. A stent adds an upfront expense during surgery, while possible savings from fewer glaucoma medications or delayed additional surgery may accumulate over many years.
The Canadian evaluation illustrated this difference. The combined procedure was projected to be cost-saving over a lifetime and a 15-year base case, but the five-year scenario instead showed an additional cost of CAD 446.90 and a cost-effectiveness ratio of CAD 32,227.80 per QALY.
That five-year estimate remained below the study’s CAD 50,000 threshold, but the apparent cost-saving advantage no longer held. The example demonstrates why a conclusion based on lifetime projections may differ from one based on a shorter planning period.
Disease severity also affected the estimates. In the German analysis, the reported cost-effectiveness ratio was €10,955 per QALY for moderate glaucoma compared with €60,269 per QALY for advanced disease, with the same procedure cost but a smaller modeled quality-of-life gain in the advanced group.
Across the eight studies, estimated QALY gains ranged from approximately 0.005 to 0.17. Because these gains were small, even modest changes in assumed effectiveness could substantially alter the calculated cost-effectiveness ratio.
Most models also extended beyond the two-year clinical trial follow-up. Some assumed treatment effectiveness would decline by 5% annually through year ten and disappear afterward, while others projected benefits for ten years or a lifetime without clearly specifying the projection method.
Funding and Evidence Limitations
The review identified important limitations in the evidence base. Six of the eight evaluations received funding from Glaukos Corporation, the device manufacturer, and at least one co-author in five studies was employed by the manufacturer.
Six evaluations modeled the iStent inject, and their clinical effectiveness estimates relied substantially on the same two-year pivotal trial. As a result, eight favorable economic models do not necessarily represent eight independent confirmations of long-term clinical benefit.
The models also approached costs from different perspectives. Six adopted a payer or health-system perspective, while two used a societal perspective. None evaluated costs from the perspective of a hospital or provider managing an annual operating budget.
This distinction matters because the organization paying for the implant may not be the same organization that benefits from lower medication spending or fewer later procedures. A treatment may look economically attractive across an entire healthcare system while creating an immediate financial challenge for an individual hospital.
All eight evaluations came from high-income healthcare systems. The review therefore does not establish that the same economic results would apply in lower-income settings, including the Philippines, where procedure costs, medicine prices, insurance coverage, and access to ophthalmic care can differ substantially.
What Patients Should Ask Before Considering a Glaucoma Stent
Economic evaluations can inform healthcare policy, but an individual treatment decision also depends on clinical need, safety, expected benefit, and affordability. A glaucoma stent should not be selected solely because an economic model predicts savings.
During an eye appointment, an ophthalmologist may assess intraocular pressure using tonometry, examine the drainage angle with gonioscopy, and evaluate the optic nerve and visual field. These tests help establish the type and severity of glaucoma and guide treatment discussions.
Patients considering combined cataract surgery and stent implantation can ask whether the device is appropriate for their glaucoma stage, how it may affect their need for medication, what complications are possible, and what costs their insurance or health coverage will pay.
They should also clarify whether quoted expenses include the implant, surgeon’s fees, facility charges, follow-up appointments, and ongoing medication. Actual out-of-pocket costs may differ from the total costs used in an economic model.
When should you see an eye doctor? Arrange an eye examination if you have glaucoma risk factors, have been advised to monitor eye pressure, or notice changes in your vision. Sudden vision loss, severe eye pain, or a painful red eye with blurred vision or nausea requires urgent medical assessment.
The next practical step is to discuss your glaucoma diagnosis and cataract treatment options with an ophthalmologist, then request a clear estimate of the expected benefits, risks, and personal costs. The review suggests that iStent-based treatment may be cost-effective in selected patients over longer periods, but reliable decisions require evidence that fits the patient’s clinical circumstances and local healthcare costs.
