What Is a Glaucoma Stent? Understanding Its Role in Eye Health

Start with what a glaucoma stent does

A glaucoma stent is a small implanted device that creates a pathway for fluid to leave the eye and help lower eye pressure. The term can refer to different devices.

Eye pressure rises when fluid inside the eye does not drain well enough. Pressure that stays too high can damage the optic nerve, the structure that carries visual information to the brain. A stent is intended to improve fluid movement; it does not restore optic-nerve damage that has already occurred.

Two examples are the iStent Trabecular Micro-Bypass Stent and the XEN Gel Stent. Ask which device your eye doctor is discussing and what pressure goal the treatment is meant to reach.

The XEN Gel Stent is a hydrophilic, 6-millimeter tube made from cross-linked porcine gelatin. Its design allows fluid to move from inside the eye toward the space beneath the conjunctiva, the clear tissue over the white part of the eye.

The XEN63 has a larger inner opening than the XEN45. That opening is designed to reduce resistance to fluid flow and may improve pressure lowering. Its outside diameter is about 12% larger than the XEN45’s, so the two devices are related but not identical.

In a study of 84 glaucomatous eyes, mean pressure was 12.7 ± 4.8 mm Hg with XEN63 and 15.5 ± 5.1 mm Hg with XEN45. Both devices reduced the need for pressure-lowering medicines in that analysis. The reduction was −3.1 ± 0.9 medicines with XEN63 and −2.1 ± 1.8 medicines with XEN45. Those results describe that study group, not what you should expect personally.

See how the drainage pathway changes

The eye’s natural drainage system moves fluid through two main pathways. One is the trabecular meshwork, a sieve-like tissue near the drainage angle. The other is the uveoscleral pathway, which carries fluid through surrounding tissues. About 75% of resistance to fluid leaving the human eye is located in the trabecular meshwork.

A trabecular-bypass stent works with the eye’s natural drainage route. It helps fluid pass through or around resistance in the trabecular pathway, rather than directing fluid to a surface bleb. This approach is used by devices such as the iStent in selected situations.

A subconjunctival drainage stent uses a different route. It creates a channel from the front part of the eye to the space beneath the conjunctiva. Fluid collects there in a small filtering bleb.

XEN treatment, for example, can involve scarring around the channel, leakage, exposure, or infection. A trabecular-bypass device has a different design and risk profile. Every procedure carries risks, and those risks differ by technique and device.

Reported results should be read with the drainage route in mind. In one trial, 84% of eyes treated with iStent and cataract surgery were medication-free at 23 months. That result came from a defined group receiving a particular device with cataract surgery.

A separate U.S. Medicare-system model found that XEN45 had higher costs and worse outcomes than trabeculectomy at five years. A model is an economic projection, not a promise about an individual treatment.

Understand when a doctor may discuss a stent

An eye doctor may discuss a stent after considering your glaucoma type, disease severity, pressure target, response to medicines, cataract status, and the particular device.
MIGS, or minimally invasive glaucoma surgery, is generally used for mild-to-moderate glaucoma because it usually lowers eye pressure less than traditional glaucoma surgery.
A micro-stent is not right for every type of glaucoma. Some narrow-angle or closed-angle cases may not benefit because the drainage pathway is different. With very advanced optic-nerve damage, your doctor may recommend a stronger surgical option to protect remaining vision.

Use your appointment to connect the treatment choice to your own findings. Ask:

• What type and stage of glaucoma do I have?
• What pressure is the treatment trying to reach?
• How much pressure reduction do you expect from this device?
• Is the procedure being considered with cataract surgery or by itself?
• What other treatments could meet the same goal?
• How would my medicines, cataract status, and optic-nerve findings change the plan?

Ask how these factors affect treatment choices. Ask your eye doctor whether the treatment fits your findings.

Open-angle glaucoma accounts for 90% of glaucoma cases in the United States. That figure describes the U.S. glaucoma population in that source; it does not mean every person with glaucoma has the same drainage anatomy or treatment options.

Know what the glaucoma evaluation measures

A glaucoma evaluation measures vision, eye pressure, the drainage angle, visual fields, and optic-nerve health. The exam may include several parts:

• An eye-chart test measures central vision.
• Eye-pressure measurement checks the pressure inside the eye.
• A drainage-angle examination checks whether the angle is open or closed.
• A visual-field test checks peripheral vision.
• An optic-nerve examination looks for cupping or other damage.
• Imaging creates a record of optic-nerve health.

Each test answers a different question. The results are considered together rather than treated as a single pass-or-fail measurement.

Tonometry measures eye pressure in millimeters of mercury, written as mm Hg. A general “normal” range is 10 to 21 mm Hg, but your ideal target pressure is individual. Your eye doctor determines the target pressure that is appropriate for you.

A pressure number therefore needs context. Your doctor may consider the optic nerve, visual field, glaucoma type, previous pressure readings, and how the pressure changes with treatment. Ask what your target is and how the proposed device is expected to help you reach it.

Bring a current list of your eye medicines and describe how regularly you can use them. Tell the eye-care team about previous laser treatment, eye surgery, and changes in vision. These details help connect the exam findings with the options discussed at the appointment.

Compare drops, laser, cataract surgery, and glaucoma surgery

Eye drops and selective laser trabeculoplasty are described as preferred first-line options for lowering eye pressure. Some patients need surgery when those treatments do not provide enough control of glaucoma progression.

Drops can lower pressure without an operation, but they require a schedule and continued monitoring. Your eye doctor can explain whether either option fits your glaucoma type and pressure target.

MIGS can be combined with cataract surgery, while cataract surgery alone may also lower eye pressure and reduce glaucoma medicine use. The effect of the cataract procedure and the effect of the stent should be discussed separately so you understand what each part is intended to do.

Compared with traditional glaucoma surgery, MIGS generally has a better safety profile and a faster recovery. Its pressure-lowering effect is usually less pronounced, so it may not meet the needs of advanced glaucoma or a very low pressure target.

Traditional glaucoma surgery may lower pressure more than MIGS, but recovery can be longer and serious complications can occur. Reported success rates for trabeculectomy with mitomycin C and tube-shunt surgery ranged from 82.7% to 96.1% at one year and from 67% to 84.9% at three years. These are reported ranges from particular studies, not a forecast for your eye.

MIGS effectiveness may decrease over time, and long-term evidence is more limited than it is for traditional filtering surgery. MIGS may not be suitable when glaucoma requires a large pressure reduction such as 40% from baseline, as can occur in advanced glaucoma.

A micro-stent does not rule out future eye drops, laser treatment, or additional surgery if more treatment is needed. Treatment can change as pressure, visual fields, and optic-nerve findings change. Ask what the next option would be if the first procedure does not reach your pressure target.

Put combined cataract surgery results in context

A pivotal iStent inject trial included 505 eyes: 387 received the stent with cataract surgery, and 118 received cataract surgery alone. The participants had mild-to-moderate open-angle glaucoma, cataracts, pressure-lowering treatment, and a preoperative pressure of 24 mm Hg or less.

At 24 months, 75.8% of the iStent group had at least a 20% reduction in eye pressure, compared with 61.9% after cataract surgery alone. Mean pressure fell by 7.0 ± 4.0 mm Hg with combined treatment and 5.4 ± 3.7 mm Hg with cataract surgery alone.

The numbers measure pressure outcomes in that trial group. They do not show that every person having cataract surgery should receive a stent.

The cited trials were not designed to show that adding the iStent lowered pressure more than cataract surgery alone, and they did not include a washout pressure measurement.
Most MIGS trial participants had mild-to-moderate open-angle glaucoma with elevated eye pressure. Results from that group may not apply to every patient group, especially when the glaucoma type, severity, pressure target, or treatment history is different.

Use the trial as a question prompt rather than a personal prediction. Ask how your cataract, glaucoma stage, current pressure, medicines, and target pressure compare with the people included in the study. Ask what result your doctor will measure and when follow-up will show whether the plan is working.

Weigh durability, risks, and follow-up

A successful XEN stent may lower eye pressure for several years, but results vary. Scar tissue can block the stent, and additional treatment may be needed if pressure rises again. If a XEN stent does not control pressure, options can include further treatment, traditional surgery, or a tube-shunt procedure.

MIGS effectiveness may also decrease over time. Long-term evidence is more limited than it is for traditional filtering surgery, so ask how long the available evidence follows the particular device being discussed.

Reported early complications of XEN implantation include pressure that is too low, blockage, choroidal detachment, stent exposure, wound or bleb leaks, and malignant glaucoma. The reported ranges included:

• Choroidal detachment: 0–15%.
• Stent exposure: 1.1–2.3%.
• Wound or bleb leaks: 2.1%.
• Malignant glaucoma: 2.2%.
• Hypotony maculopathy, a pressure-related effect on the macula: 1.9–4.6%.
• Occlusion, or blockage: 3.9–8.8%.

These figures came from a systematic review of XEN studies and describe reported complications, not your personal risk.

Reported mid-term complications included stent movement at 1.5%, eyelid drooping at 1.2%, eye infection at 0.4–3%, macular swelling at 1.5–4.3%, and a thickened filtering bleb at 8.8%.

The systematic review included 48 studies with follow-up of up to five years. Follow-up time, device type, glaucoma type, and surgical technique affect how well a complication estimate applies to a particular situation.

Follow-up appointments let the surgical team monitor pressure, healing, the drainage pathway, and possible complications. Keep the follow-up schedule your eye-care team gives you. If a stent becomes exposed or you have signs of infection after surgery, seek prompt surgical medical care.

Ask what the full treatment may cost

Glaucoma treatment prices vary by device, procedure, facility, anesthesia, operating-room charges, follow-up, whether cataract surgery is combined, and insurance coverage. A U.S. cost estimate puts glaucoma laser treatments between $1,000 and $2,000, while more involved surgeries average around $5,000 before added anesthesia and operating-room fees.

The same source reports about $4,200 for traditional trabeculectomy and closer to $6,300 for newer microshunt procedures. A reported national eye-procedure range is $425 to $7,395, depending on the treatment and facility. These figures are broad published estimates, not a Minnetonka-specific quote.

A U.S. Medicare-system economic model estimated one-year total costs of $10,512 for XEN45 and $8,649 for trabeculectomy. In that model, XEN45 had higher costs and worse outcomes than trabeculectomy at five years. The result belongs to that model’s assumptions, time horizon, and Medicare setting; it is not a bill estimate for you.

Coverage can vary by payer and by the exact procedure. Coverage for a second iStent varies: many, but not all, payers may not cover it. Before treatment, ask what the plan covers and what you may owe for the device, surgeon, facility, anesthesia, medicines, testing, and follow-up. Ask for the total expected out-of-pocket amount and what happens if an additional procedure is needed.

Bring these questions to your eye appointment

An eye appointment is the right place to connect your examination results with treatment choices. Bring these questions:

• What type and stage of glaucoma do I have?
• What is my target eye pressure, and how was it chosen?
• Which device or procedure are you recommending, and what drainage route does it use?
• Is it intended for my glaucoma type and pressure goal?
• Would drops, laser treatment, cataract surgery alone, or another operation be reasonable alternatives?
• What pressure reduction is realistic for this procedure?
• What will recovery and follow-up involve?
• Which complications should prompt a call or urgent care?
• How long is the available evidence for this device?
• What is the full expected cost, including facility, anesthesia, testing, medicines, and follow-up?
• What does my insurance cover, and what could I owe if more treatment is needed?

A cost model estimated one-year totals of $10,512 for XEN45 and $8,649 for trabeculectomy, but those figures came from a U.S. Medicare-system model rather than a personal quote. Use them only as a prompt to ask how your estimate is calculated.

Write down the answers in plain language, including the target pressure, expected follow-up schedule, alternatives, and total estimated cost. Ask your eye doctor to explain any device name or pressure number you do not recognize. A clear plan should identify what will be measured after treatment and what the next option would be if the target is not reached.

Get prompt help for postoperative warning signs

An exposed stent or signs of infection after surgery require prompt surgical medical care. Conjunctival erosion and an exposed XEN stent can cause a serious eye infection, so do not wait for a routine appointment if your surgical team has told you that the implant is exposed or if infection is suspected.

A leaking XEN bleb is uncommon but potentially sight-threatening. Contact the surgical team promptly about suspected postoperative leakage or infection.

An ocular emergency should not be handled through the Northwest Eye contact form. Please use the emergency eye-care route available to you instead. For postoperative concerns that are not clearly an emergency, contact the surgical team using the instructions given after your procedure.

Do not skip scheduled follow-up after a stent procedure. Monitoring helps the surgical team check pressure, healing, blockage, leakage, movement, and infection.

Book an appointment to discuss your options

A glaucoma stent is one way to improve fluid drainage and lower eye pressure, but the right choice depends on your glaucoma type, optic-nerve health, target pressure, medicines, cataract status, and the device being considered. A qualified eye-care professional can decide whether a stent or another treatment is appropriate for you after reviewing your examination. At Northwest Eye in Minnetonka, bring the questions above to an eye appointment so you can discuss findings, alternatives, follow-up, and expected costs.

Questions to ask about glaucoma stents and cost

How much does a glaucoma stent cost in the United States?

There is no single price for a glaucoma stent. Published estimates include about $5,000 for more involved glaucoma surgery before added anesthesia and facility fees, while one Medicare-system model estimated a one-year total of $10,512 for XEN45. These figures are not a Minnetonka quote and may not reflect your procedure or coverage.

What can change the out-of-pocket cost of glaucoma stent surgery?

Your total may change based on the device, surgeon, facility, anesthesia, testing, medicines, follow-up, combined cataract surgery, and insurance coverage. Ask for a written estimate that separates each charge and explains what happens if the stent does not reach the pressure goal. Coverage can differ by payer and procedure, so confirm your benefits before treatment.

Does a glaucoma stent cure glaucoma or restore lost vision?

No. A stent is intended to lower eye pressure and help slow or control glaucoma progression; it cannot restore optic-nerve damage or vision already lost. Keep follow-up visits so your doctor can monitor pressure and treatment response.

What should I ask before agreeing to a glaucoma stent?

Ask which device and drainage route are proposed, what type and stage of glaucoma you have, and what pressure target the procedure addresses. Also ask about alternatives, expected pressure reduction, recovery, follow-up, complications, evidence duration, insurance coverage, and total out-of-pocket cost. These questions help you compare the plan with your individual findings.