Glaucoma Surgery Explained: Trabeculectomy, MIGS, and What to Expect

When eye drops and laser treatments aren’t enough to stop glaucoma from damaging your vision, surgery becomes the next step. But not all glaucoma surgeries are the same. Two main paths exist: the long-standing trabeculectomy and the newer wave of minimally invasive glaucoma surgeries (MIGS). Each has clear strengths, risks, and ideal candidates. Understanding the differences isn’t just about medical jargon-it’s about choosing the right option for your vision and lifestyle.

What Trabeculectomy Actually Does

Trabeculectomy isn’t new. Developed in the 1960s, it’s still the benchmark for lowering eye pressure when other treatments fail. The goal? Create a new drainage channel so fluid can escape the eye more easily, reducing pressure on the optic nerve.

The surgery involves making a small flap in the white part of the eye (sclera), removing a tiny piece of the drainage tissue (trabecular meshwork), and letting fluid slowly leak out under the conjunctiva. That fluid collects into a small blister-like pocket called a bleb, which sits just under the eyelid. It’s invisible to most people, but it’s critical to the procedure’s success.

This surgery typically takes about an hour. Patients usually go home the same day, but recovery is slow and careful. For the first 3 to 6 months, frequent checkups are needed. Doctors may need to adjust sutures, massage the bleb, or perform a needling procedure to keep it open. Without this attention, the bleb can scar over and stop working.

Success rates are high: 85-90% of patients reach their target eye pressure within the first year. Pressure levels often drop to 5-15 mmHg, which is ideal for advanced glaucoma. But there’s a cost. About 5-15% of patients face serious complications like low eye pressure (hypotony), infection (endophthalmitis), or a leaking bleb. Long-term, 10-20% of blebs fail within five years. That’s why it’s usually reserved for patients who need very low pressure or have already tried other surgeries.

What MIGS Is-and Isn’t

MIGS stands for Minimally Invasive Glaucoma Surgery. It’s not one procedure-it’s a whole family of them, all designed to be safer and faster than trabeculectomy. Introduced around 2012 with the iStent, MIGS has exploded in popularity. By 2025, nearly 65% of standalone glaucoma surgeries in the U.S. are MIGS procedures.

These surgeries use tiny incisions-usually less than 1.5 millimeters-and often happen at the same time as cataract surgery. That means less overall trauma, quicker healing, and fewer restrictions afterward. Most patients see clear vision within a week or two, compared to 4-6 weeks for trabeculectomy.

Popular MIGS devices include:

• iStent inject: Two tiny stents placed in the eye’s natural drainage system. Reduces pressure by 20-30%.
• Hydrus Microstent: A small metal scaffold that opens the drainage channel. Works well with cataract surgery.
• Xen Gel Stent: A soft, 6mm tube that drains fluid to the surface under the conjunctiva. Similar to trabeculectomy but less invasive.
• GATT (Gonioscopy-Assisted Transluminal Trabeculotomy): A catheter is threaded around the drainage canal to open it up. Can reduce pressure by 30-35%.

The pressure reduction from MIGS is more modest than trabeculectomy-typically 15-18 mmHg, with a 20-30% drop from baseline. But that’s often enough for mild-to-moderate glaucoma. Patients also go from an average of 2-3 medications down to 1 or none. Complication rates are low: only 1-3% risk of serious issues like infection or bleeding.

Trabeculectomy vs. MIGS: The Real Differences

It’s not just about pressure numbers. The real choice comes down to how much risk you’re willing to take, how much recovery time you have, and how advanced your glaucoma is.

Comparison of Trabeculectomy and MIGS

Feature	Trabeculectomy	MIGS
Typical IOP Reduction	40-60% (5-15 mmHg)	20-30% (15-18 mmHg)
Procedure Time	60 minutes	15-30 minutes
Recovery Time	4-6 weeks	1-2 weeks
Post-op Monitoring	3-6 months	1-2 months
Complication Risk	5-15%	1-3%
Best For	Advanced glaucoma, very low target pressure	Mild-to-moderate glaucoma, patients wanting faster recovery
Cost (per eye)	$4,200	$6,300 (Xen), $2,500-$4,000 (iStent)

Where Laser Fits In-And Why It’s Often First

Before you even think about surgery, laser treatment is usually the first step. Selective Laser Trabeculoplasty (SLT) uses a low-energy laser to stimulate the eye’s natural drainage system. It’s quick-5 to 10 minutes-and can be done in the doctor’s office. No cuts. No stitches. No downtime.

The 2023 LiGHT trial changed everything. It showed SLT was just as good as daily eye drops at controlling pressure over three years. About 75% of patients maintained target pressure without needing more treatment. That’s why experts now recommend SLT as the first-line therapy for open-angle glaucoma.

Even newer versions like Direct Selective Laser Trabeculoplasty (DSLT) can treat the entire drainage angle automatically-no manual aiming needed. But it can cause slightly more post-op irritation and slightly less pressure lowering than traditional SLT.

The takeaway? SLT isn’t just a backup. It’s often the smartest first move. Many patients never need surgery at all.

Who Gets Which Surgery?

There’s no one-size-fits-all. The decision depends on three things: how far your glaucoma has progressed, your target pressure, and your life situation.

• Mild-to-moderate glaucoma: MIGS is the go-to. Especially if you’re already having cataract surgery. You get better pressure control, fewer meds, and minimal disruption to your life.
• Advanced glaucoma: Trabeculectomy or tube shunts are still the best bet. If your pressure needs to be below 15 mmHg to protect your vision, MIGS often can’t deliver enough.
• Younger patients: They tend to need long-term pressure control. Trabeculectomy may be preferred because it lasts longer, even with its risks.
• Older patients or those with other health issues: MIGS is safer. Less recovery time means less stress on the body.

The trend is clear: doctors are moving toward earlier intervention. Instead of waiting until medications fail, many now use SLT or MIGS right after diagnosis. That’s because glaucoma damage is permanent. The earlier you lower pressure, the more vision you save.

What Happens After Surgery?

Recovery isn’t the same for every procedure.

After trabeculectomy, you’ll need to avoid heavy lifting, bending over, or rubbing your eye for weeks. You’ll use steroid and antibiotic drops for months. Bleb care is essential-your doctor may need to do a bleb needling procedure to prevent scarring. Missing a follow-up can mean losing the surgery’s benefit.

After MIGS, you’ll still use eye drops, but usually for just a few weeks. Most people return to normal activities within days. There’s no bleb to monitor, no needling, and no risk of sudden pressure crashes.

Both require lifelong monitoring. Glaucoma doesn’t go away after surgery. You still need regular eye exams to check your pressure, optic nerve, and visual field.

The Future of Glaucoma Surgery

The field is evolving fast. Suprachoroidal shunts-devices placed between the layers of the eye wall-are showing promise as standalone treatments. New MIGS devices are being tested to work without cataract surgery. Some are even designed to deliver medication slowly over time.

But the biggest shift isn’t technological-it’s philosophical. Glaucoma care is moving from “wait until it’s bad” to “act early and often.” SLT and MIGS aren’t just alternatives to trabeculectomy. They’re part of a new ladder of care: laser first, MIGS next, trabeculectomy only if needed.

The data supports this. MIGS adoption is growing 10% per year. The global market for glaucoma surgery is projected to hit $6.8 billion by 2029. But the real win isn’t in dollars-it’s in preserved vision. More people are keeping their sight longer because treatment starts sooner.

What Should You Do Next?

If you’ve been told you need surgery, ask these questions:

• What’s my current eye pressure, and what’s my target?
• Have I tried SLT? If not, why not?
• Is my glaucoma mild, moderate, or advanced?
• What’s the expected pressure reduction with each option?
• How many follow-ups will I need? What’s the recovery time?
• What are the risks specific to my age and health?

There’s no rush. Glaucoma progresses slowly. Take time to understand your options. Talk to your doctor about your goals. Do you want to eliminate eye drops? Avoid hospital visits? Preserve your ability to drive or read? Your priorities matter as much as your numbers.

If your glaucoma is stable and you’re doing well on medication, don’t rush into surgery. But if your pressure is rising or your vision is changing, don’t wait either. Talk to your doctor about SLT or MIGS now-before you need the bigger surgery.