Glaucoma Surgery: Trabeculectomy, MIGS, and What to Expect

When Glaucoma Medications Aren’t Enough

If you’ve been told your eye pressure won’t stay low enough with drops or laser, surgery might be the next step. Glaucoma doesn’t cause pain, but it quietly damages your optic nerve - and once vision is lost, it’s gone for good. Surgery doesn’t cure glaucoma, but it can stop or slow the damage by lowering pressure inside the eye. Two main types of surgery are used today: trabeculectomy and MIGS (Minimally Invasive Glaucoma Surgery). Each has different goals, risks, and recovery times.

Trabeculectomy: The Long-Standing Gold Standard

Trabeculectomy has been around since the 1960s and is still the most effective surgery for lowering eye pressure in advanced glaucoma. The procedure creates a tiny channel under the white part of the eye (sclera), allowing fluid to drain out and form a small blister-like pocket (called a bleb) under the eyelid. This bleb acts like a pressure relief valve.

On average, trabeculectomy lowers eye pressure by 40-60%. Most patients end up with pressures between 5 and 15 mmHg - low enough to protect vision in severe cases. About 85-90% of patients reach their target pressure within the first year, according to data from Mass Eye and Ear in 2023.

But there’s a catch. The surgery takes about an hour, and recovery is slow. You’ll need weekly check-ups for the first few months. The bleb can leak, get infected, or scar over. About 10-15% of people have a leak in the first few weeks. Long-term, 10-20% of blebs fail within five years. There’s also a small but serious risk of infection inside the eye (endophthalmitis), which happens in about 0.5-2% of cases.

Because of these risks, trabeculectomy isn’t the first choice anymore - it’s reserved for when other treatments fail. It’s often used for younger patients who need lifelong pressure control, or for those with advanced nerve damage.

MIGS: Smaller Incisions, Faster Recovery

MIGS procedures changed the game. They started appearing around 2012, and today, they make up about 65% of all standalone glaucoma surgeries in the U.S. These surgeries use tiny devices - smaller than a grain of rice - inserted through a micro-incision (less than 1.5mm). Many are done at the same time as cataract surgery, so you’re not having two separate operations.

Popular MIGS options include:

• iStent inject: Two tiny stents placed in the eye’s natural drainage system. Lowers pressure by 20-30%.
• Hydrus Microstent: A small metal scaffold that opens up the drainage channel. Works well with cataract surgery.
• Xen Gel Stent: A soft, 6mm tube that drains fluid to the surface. More effective than iStent but costs more.
• GATT (Gonioscopy-Assisted Transluminal Trabeculotomy): A thread is threaded through the drainage system to open it up. Can lower pressure by 30-35%.

MIGS doesn’t lower pressure as much as trabeculectomy - usually to 15-18 mmHg. But that’s often enough for mild to moderate glaucoma. Most patients reduce their eye drops by 1.5 to 2 medications after surgery.

The big advantage? Safety. Complication rates are under 5%, and most people see clearly within 1-2 weeks. No bleb means no risk of infection from a leak. You can go back to normal activities faster. There’s no need for frequent post-op visits - usually just 1-2 months of monitoring.

What About Laser? SLT Is Still First

Before surgery, most doctors try Selective Laser Trabeculoplasty (SLT). It’s quick, painless, and takes less than 10 minutes. SLT uses a laser to stimulate the eye’s drainage system without damaging tissue. It’s not surgery, but it’s often the first step.

The 2023 LiGHT trial showed SLT works just as well as daily eye drops for controlling pressure over three years. About 75% of patients stayed at target pressure without needing more treatment. That’s why most guidelines now say SLT should come before drops, not after.

There’s even a newer version called DSLT (Direct Selective Laser Trabeculoplasty), which treats the whole drainage angle automatically without touching the eye. It’s promising, but it can cause more temporary irritation and doesn’t lower pressure quite as much as traditional SLT.

Comparing Trabeculectomy and MIGS Side by Side

Costs vary by region and insurance, but MIGS devices are often more expensive than the materials used in trabeculectomy. That’s why some insurers still prefer trabeculectomy for advanced cases - it’s cheaper long-term.

Who Gets Which Surgery?

There’s no one-size-fits-all answer. Your surgeon will look at:

• How advanced is your glaucoma? If your vision is already fading, you likely need trabeculectomy. If you’re just starting to lose peripheral vision, MIGS may be enough.
• What’s your target pressure? If you need pressure below 15 mmHg, trabeculectomy is more likely to get you there.
• Are you having cataract surgery? MIGS fits right into that procedure - no extra incisions needed.
• How well can you follow up? Trabeculectomy needs lots of visits. If you live far from the clinic or have trouble getting time off, MIGS is easier to manage.
• Age and life expectancy? Younger patients may benefit from trabeculectomy because they need decades of pressure control. Older patients often prefer MIGS for safety and speed.

Many surgeons now use a stepwise approach: SLT first, then MIGS if pressure creeps up, and trabeculectomy only if those fail. This shift is backed by the 2025 update to the American Academy of Ophthalmology’s guidelines.

What’s Next for Glaucoma Surgery?

The field is changing fast. New devices are being tested in the suprachoroidal space - that’s the area behind the eye’s drainage system. These could offer better pressure control than MIGS without the risks of trabeculectomy.

Long-term data on MIGS is still limited because the procedures are so new. But early results are encouraging. Most patients stay stable for 3-5 years. As more data comes in, MIGS may replace trabeculectomy for many cases - especially if costs come down.

For now, the best approach is personalized. If you’ve been told you need surgery, ask: “What’s my target pressure? Why this surgery over another? What happens if it doesn’t work?” You’re not just choosing a procedure - you’re choosing a long-term plan to protect your vision.

Next Steps: What to Do If You’re Considering Surgery

Don’t rush. Talk to your ophthalmologist about:

• Your current eye pressure and how much it’s changed over the last year.
• How much vision loss you’ve had - and how fast it’s progressing.
• Whether you’re planning cataract surgery soon.
• Your ability to attend follow-up visits.
• Your goals: Do you want to stop drops? Avoid long-term risks? Maximize pressure control?

Ask for a copy of your latest visual field test and optic nerve scan. These help determine how urgent your situation is. If your pressure is stable and your vision hasn’t changed much, you might not need surgery right away - SLT or a change in drops could be enough.

Glaucoma moves slowly. But when it comes to surgery, the timing matters. Waiting too long can mean losing vision you can’t get back. Choosing the right procedure - and the right time - gives you the best shot at keeping your sight for life.