The advent of iStent® technologies (Glaukos) has shifted the landscape of glaucoma surgery, providing a less invasive alternative to traditional options such as trabeculectomy. This development not only reduces surgical risks but also prompts a reevaluation of treatment strategies and timing for glaucoma patients.
RECONSIDERING TRADITIONAL GLAUCOMA TREATMENT ALGORITHMS
Historically, glaucoma management has relied on a stepwise escalation from topical medications to increasingly aggressive interventions as IOP progresses. However, treatment with multiple medications often fails to adequately control disease progression,1 hindered by compliance challenges, side effects, and application difficulties. Invasive procedures such as trabeculectomy have been reserved for advanced cases due to their higher risk profiles.
Recent evidence, however, supports early surgical intervention as a means to slow disease progression more effectively than medication alone, even in patients with well-controlled IOP.2 This highlights the need for safer, less invasive surgical alternatives that can be implemented earlier in the disease course.
IMPACT OF ISTENT inject® W ON SURGICAL PRACTICES
At Hospital Clínico San Carlos in Madrid, we conducted a 13-year retrospective study analyzing approximately 13,000 procedures from 2010 to 2022, of which nearly 10,000 were cataract extractions and close to 3,000 were glaucoma surgeries, predominantly for primary open-angle glaucoma (unpublished data, 2010–2022; Figure).
Figure. Trends in glaucoma surgery: 2010–2022.
Key findings include the following:
- Shift toward MIGS. Since 2018, we observed a notable decline in traditional procedures like trabeculectomy and an increase in MIGS, particularly with the iStent inject®(Glaukos).
- Reduction in surgical risks. Moving away from trabeculectomy has lowered surgical risks for patients, as MIGS procedures are less invasive and offer a more favorable safety profile.
- Missed opportunities for combined surgery. A substantial number of glaucoma patients underwent cataract surgery alone without concurrent MIGS, representing missed opportunities for early surgical intervention and potentially better disease control.
Cost-Effectiveness of iStent inject® in Spain
To support the adoption of iStent inject® at a broader level, a study was conducted to evaluate the cost-effectiveness of the device within the Spanish health care system.3 Highlights from the study include the following:
- Effectiveness. iStent inject® combined with cataract surgery effectively reduces IOP and medication dependence, supporting improved disease control.
- Cost analysis. Although the upfront cost is higher than cataract surgery alone, the health benefits justify the expense, as measured by quality-adjusted life years.
- Conclusion. iStent inject® proves to be a cost-effective option in Spain, reinforcing its use in earlier stages of glaucoma treatment. Notably, similar studies across various health care systems, including in Canada, France, Italy, Colombia, and Japan, demonstrate that the iStent® technologies are cost-effective worldwide.4-11
Advantages of iStent inject® W Technology
The iStent inject® W (Glaukos) device, a small, biocompatible implant placed in the trabecular meshwork, facilitates physiological outflow through Schlemm canal, with several key advantages:
- Minimally invasive procedure. The surgery is straightforward, is reproducible, and has an overall safety profile similar to cataract surgery alone.12
- Reduction in medication burden. Patients typically experience decreased dependence on topical medications, improving adherence and quality of life.13
- Preservation of future options. Due to its minimally invasive nature, iStent inject® W preserves options for future interventions if needed.
CONCLUSION
The introduction of iStent inject® W has transformed the glaucoma surgical approach, significantly reducing the reliance on trabeculectomy and its associated risks. Data support the clinical and cost-effectiveness of integrating iStent® technologies into earlier stages of glaucoma care.3-11
1. Malihi M, Moura Filho ER, Hodge DO, Sit AJ. Long-term trends in glaucoma-related blindness in Olmsted County, Minnesota. Ophthalmology. 2014;121(1):134-141.
2. Musch DC, Gillespie BW, Lichter PR, Niziol LM, Janz NK; CIGTS Study Investigators. Visual field progression in the Collaborative Initial Glaucoma Treatment Study the impact of treatment and other baseline factors. Ophthalmology. 2009;116(2):200-207.
3. Teus MA, Belda JI, Lavín C, et al. Cost-effectiveness analysis of iStent inject implantation during cataract surgery compared to cataract surgery alone for mild to moderate open-angle glaucoma patients in Spain. Expert Rev Ophthalmol. 2021;16(4):319-328.
4. Ordóñez JE, Ordóñez A, Osorio UM. Cost-effectiveness analysis of iStent trabecular micro-bypass stent for patients with open-angle glaucoma in Colombia. Curr Med Res Opin. 2019;35(2):329-340.
5. Patel V, Ahmed I, Podbielski D, et al. Cost-effectiveness analysis of standalone trabecular micro-bypass stents in patients with mild-to-moderate open-angle glaucoma in Canada. J Med Econ. 2019;22(4):390-401.
6. Ahmed IIK, Podbielski DW, Patel V, et al. A Canadian cost-utility analysis of 2 trabecular microbypass stents at time of cataract surgery in patients with mild to moderate open-angle glaucoma. Ophthalmol Glaucoma. 2020;3(2):103-113.
7. Nieland K, Labbé A, Schweitzer C, et al. A cost-effectiveness analysis of iStent inject combined with phacoemulsification cataract surgery in patients with mild-to-moderate open-angle glaucoma in France. PLoS One. 2021;16(6):e0252130.
8. Fea AM, Cattel F, Gandolfi S, et al. Cost-utility analysis of trabecular micro-bypass stents (TBS) in patients with mild-to-moderate open-angle glaucoma in Italy. BMC Health Serv Res. 2021;21(1):824.
9. Sood S, Heilenbach N, Sanchez V, et al. Cost-effectiveness analysis of minimally invasive trabecular meshwork stents with phacoemulsification. Ophthalmol Glaucoma. 2022;5(3):284-296.
10. Igarashi A, Ishida K, Shoji N, et al. iStent inject and cataract surgery for mild-to-moderate primary open angle glaucoma in Japan: a cost-utility analysis. Int J Ophthalmol. 2022;15(6):954-961.
11. Guedes RAP, Souza CP, Dias LLdS, et al. A Brazilian cost-utility analysis of trabecular micro-bypass with iStent inject for the treatment of open-angle glaucoma. Rev Bras Oftalmol. 2022;81.
12. Samuelson TW, Sarkisian SR Jr, Lubeck DM, et al; iStent inject Study Group. Prospective, randomized, controlled pivotal trial of an ab interno implanted trabecular micro-bypass in primary open-angle glaucoma and cataract: two-year results. Ophthalmology. 2019;126(6):811-821.
13. Samuelson TW, Singh IP, Williamson BK, et al. Quality of life in primary open-angle glaucoma and cataract: an analysis of VFQ-25 and OSDI from the iStent inject pivotal trial. Am J Ophthalmol. 2021;229:220-229.
INDICATIONS FOR USE: The iStent® Trabecular Micro-Bypass System is intended to reduce intraocular pressure safely and effectively in patients diagnosed with primary open-angle glaucoma, pseudoexfoliative glaucoma or pigmentary glaucoma. The device is safe and effective when implanted in combination with cataract surgery in those subjects who require intraocular pressure reduction and/or would benefit from glaucoma medication reduction. The device may also be implanted in patients who continue to have elevated intraocular pressure despite prior treatment with glaucoma medications and conventional glaucoma surgery. CONTRAINDICATIONS: The iStent® Trabecular Micro-Bypass Stent is contraindicated under the following circumstances or conditions: • In eyes with primary angle closure glaucoma, or secondary angle-closure glaucoma, including neovascular glaucoma, because the device would not be expected to work in such situations • In patients with retrobulbar tumor, thyroid eye disease, Sturge-Weber Syndrome or any other type of condition that may cause elevated episcleral venous pressure. WARNINGS/PRECAUTIONS: For prescription use only. This device has not been studied in patients with uveitic glaucoma. Do not use the devices if the Tyvek® lid has been opened or the packaging appears damaged. In such cases, the sterility of the device may be compromised. iStent is MR-Conditional. Physician training by Glaukos personnel is required prior to use of this device. Do not re-use the stent(s) or inserter, as this may result in infection and/or intraocular inflammation, as well as occurrence of potential postoperative adverse events. There are no known compatibility issues with the iStent and other intraoperative devices (e.g., viscoelastics) or glaucoma medications. Unused product & packaging may be disposed of in accordance with facility procedures. Implanted medical devices and infected products must be disposed of as medical waste.
INDICATIONS FOR USE: The iStent inject® is intended to reduce intraocular pressure safely and effectively in patients diagnosed with primary open-angle glaucoma, pseudo-exfoliative glaucoma or pigmentary glaucoma. The iStent inject® can deliver two (2) stents on a single pass, through a single incision. The implant is designed to stent open a passage through the trabecular meshwork to allow for an increase in the facility of outflow and a subsequent reduction in intraocular pressure. The device is safe and effective when implanted in combination with cataract surgery in those subjects who require intraocular pressure reduction and/or would benefit from glaucoma medication reduction. The device may also be implanted in patients who continue to have elevated intraocular pressure despite prior treatment with glaucoma medications and conventional glaucoma surgery. CONTRAINDICATIONS: The iStent inject® System is contraindicated under the following circumstances or conditions: • In eyes with primary angle closure glaucoma, or secondary angle-closure glaucoma, including neovascular glaucoma, because the device would not be expected to work in such situations • In patients with retrobulbar tumor, thyroid eye disease, Sturge-Weber Syndrome or any other type of condition that may cause elevated episcleral venous pressure. WARNINGS/PRECAUTIONS: • For prescription use only. • This device has not been studied in patients with uveitic glaucoma. • Do not use the devices if the Tyvek® lid has been opened or the packaging appears damaged. In such cases, the sterility of the device may be compromised. • Due to the sharpness of certain injector components (i.e. the insertion sleeve and trocar), care should be exercised to grasp the injector body. Dispose of device in a sharps container. • iStent inject® is MR-Conditional; see MRI Information below. • Physician training is required prior to use of the iStent inject® System. • Do not re-use the stent(s) or inserter, as this may result in infection and/or intraocular inflammation, as well as occurrence of potential postoperative adverse events as shown below under “Potential Complications.” • There are no known compatibility issues with the iStent inject® and other intraoperative devices (e.g., viscoelastics) or glaucoma medications. • Unused product & packaging may be disposed of in accordance with facility procedures. Implanted medical devices and contaminated products must be disposed of as medical waste. • Due to the sharpness of certain injector components (i.e. the insertion sleeve and trocar), care should be exercised to grasp the injector body • The surgeon should monitor the patient postoperatively for proper maintenance of intraocular pressure. If intraocular pressure is not adequately maintained after surgery, the surgeon should consider an appropriate treatment regimen to reduce intraocular pressure.
INDICATION FOR USE: The iStent inject® W, is intended to reduce intraocular pressure safely and effectively in patients diagnosed with primary open-angle glaucoma, pseudo-exfoliative glaucoma or pigmentary glaucoma. The iStent inject® W, can deliver two (2) stents on a single pass, through a single incision. The implant is designed to stent open a passage through the trabecular meshwork to allow for an increase in the facility of outflow and a subsequent reduction in intraocular pressure. The device is safe and effective when implanted in combination with cataract surgery in those subjects who require intraocular pressure reduction and/or would benefit from glaucoma medication reduction. The device may also be implanted in patients who continue to have elevated intraocular pressure despite prior treatment with glaucoma medications and conventional glaucoma surgery. CONTRAINDICATIONS: The iStent inject® W System is contraindicated under the following circumstances or conditions: • In eyes with primary angle closure glaucoma, or secondary angle-closure glaucoma, including neovascular glaucoma, because the device would not be expected to work in such situations. • In patients with retrobulbar tumor, thyroid eye disease, Sturge-Weber Syndrome or any other type of condition that may cause elevated episcleral venous pressure. WARNINGS/PRECAUTIONS: • For prescription use only. • This device has not been studied in patients with uveitic glaucoma. • Do not use the device if the Tyvek® lid has been opened or the packaging appears damaged. In such cases, the sterility of the device may be compromised. • Due to the sharpness of certain injector components (i.e. the insertion sleeve
and trocar), care should be exercised to grasp the injector body. Dispose of device in a sharps container. • iStent inject® W is MR-Conditional; see MRI Information below. • Physician training is required prior to use of the iStent inject® W System. • Do not re-use the stent(s) or injector, as this may result in infection and/or intraocular inflammation, as well as occurrence of potential postoperative adverse events as shown below under “Potential Complications.” • There are no known compatibility issues with the iStent inject® W and other intraoperative devices. (e.g., viscoelastics) or glaucoma medications. • Unused product & packaging may be disposed of in accordance with facility procedures. Implanted medical devices and contaminated products must be disposed of as medical waste. • The surgeon should monitor the patient postoperatively for proper maintenance of intraocular pressure. If intraocular pressure is not adequately maintained after surgery, the surgeon should consider an appropriate treatment regimen to reduce intraocular pressure. • Patients should be informed that placement of the stents, without concomitant cataract surgery in phakic patients, can enhance the formation or progression of cataract. ADVERSE EVENTS: Please refer to Directions For Use for additional adverse event information. CAUTION: Please reference the Directions For Use labelling for a complete list of contraindications, warnings and adverse events.
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