Trabeculectomy
A time-tested filtering surgery that remains the gold standard for achieving very low target eye pressures when drops, laser, and MIGS aren't enough.
What Is Trabeculectomy?
Trabeculectomy is the traditional glaucoma filtering surgery, in use for decades and still considered a gold standard for achieving substantial, durable eye pressure reduction. The surgeon creates a small flap in the sclera (the white of the eye) and a tiny opening beneath it, allowing fluid to drain out of the eye into a reservoir under the conjunctiva called a bleb, where it is gradually absorbed by surrounding tissue.
Antifibrotic Medication
A major advance in trabeculectomy has been the use of antifibrotic medications — most commonly mitomycin-C, and sometimes 5-fluorouracil — applied during surgery to reduce scarring at the surgical site. Because the body's natural healing response is the main reason filtering surgeries can fail over time, these medications meaningfully improve the long-term success rate, though they also contribute to some of the specific risks discussed below.
Indications
- ✓Glaucoma that continues to progress, or remains above target pressure, despite maximum tolerated drops, laser, and/or MIGS
- ✓Advanced glaucoma where a very low target pressure is needed to protect remaining vision
- ✓Certain patients as a primary surgical choice when a large, durable pressure reduction is anticipated to be needed
Risks & Complications
- ✓Bleb-related infection (blebitis, or more rarely, endophthalmitis), a lifetime risk given the thin, filtering bleb tissue
- ✓Hypotony (eye pressure that is too low), particularly in the early post-operative period
- ✓Bleb leak, requiring monitoring or intervention
- ✓Choroidal effusion or, rarely, hemorrhage from a sudden pressure change
- ✓Cataract progression
- ✓Need for bleb revision, needling (a follow-up procedure to reduce early scar tissue), or reoperation if the bleb scars down over time
How It Compares to Tube Shunt Surgery
Two major randomized trials, the Tube Versus Trabeculectomy (TVT) study and the more recent Primary Tube Versus Trabeculectomy (PTVT) study, directly compared trabeculectomy to tube shunt surgery.1,2 Broadly, these studies found that both approaches can be highly effective, with trabeculectomy sometimes achieving lower pressures in certain populations, while tube shunts showed advantages in eyes with prior failed trabeculectomy or significant conjunctival scarring. We use this evidence, along with your specific eye anatomy and surgical history, to individualize which procedure is the better fit — see our Tube Shunt Surgery page for more detail.
Trabeculectomy is typically considered after drops, laser, and/or MIGS haven't achieved the needed pressure control, though it may be recommended earlier in more advanced disease. See our MIGS Surgery and Tube Shunt Surgery pages for how these options compare.
References
- Gedde SJ, Schiffman JC, Feuer WJ, et al. Treatment Outcomes in the Tube Versus Trabeculectomy (TVT) Study after Five Years of Follow-up. Am J Ophthalmol. 2012;153(5):789-803.
- Gedde SJ, Feuer WJ, Lim KS, et al. Treatment Outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study after 1 Year of Follow-up. Ophthalmology. 2018;125(5):650-663.
Frequently Asked Questions
Why would I need trabeculectomy instead of MIGS?
MIGS is generally reserved for mild-to-moderate glaucoma and produces a more modest pressure reduction. When a much lower target pressure is needed, or glaucoma is more advanced, trabeculectomy (or tube shunt surgery) can achieve a bigger and more durable pressure reduction.
What is the 'bleb' I've heard about?
The bleb is a small, flattened fluid reservoir that forms under the upper eyelid, where the new drainage pathway created during surgery allows fluid to filter out of the eye and be gradually absorbed. It's usually not visible unless you lift the eyelid.
How long is recovery?
Most of the critical healing happens over the first 4–6 weeks, with frequent follow-up visits during this period to fine-tune the bleb's function, though full stabilization can take a few months.
Is trabeculectomy or a tube shunt better?
It depends on your specific eye and history. Randomized trials (the TVT and PTVT studies) have compared the two directly and found each has situations where it performs better — we individualize this recommendation rather than defaulting to one over the other.
See a glaucoma specialist. Dr. Robert Gunzenhauser is Harvard-educated and UCLA fellowship-trained in glaucoma, providing expert diagnosis and treatment for Trabeculectomy at Inland Glaucoma Center in Upland, CA.