An iridectomy is a surgical procedure that removes a small piece of the iris, the colored part of your eye. It creates an opening that allows fluid to flow more freely inside the eye, preventing dangerous pressure buildup. The procedure is most commonly performed to treat or prevent angle-closure glaucoma, a condition that can cause rapid vision loss if left untreated.
How It Works
Your eye constantly produces a clear fluid called aqueous humor, which flows from behind the iris (the posterior chamber) through the pupil and into the front of the eye (the anterior chamber), where it drains out. In some people, the iris presses against the lens and blocks this flow. Fluid backs up, pressure rises in the eye, and the drainage angle at the front of the eye gets pushed closed. This is angle-closure glaucoma.
By removing a small wedge of iris tissue, an iridectomy creates an alternate pathway for fluid to pass through. Think of it like poking a relief hole in a dam: the pressure equalizes on both sides, the iris falls back into its normal position, and the drainage angle reopens. This can bring eye pressure down quickly and prevent the kind of optic nerve damage that leads to permanent blindness.
Laser Iridotomy vs. Surgical Iridectomy
Most patients today receive a laser peripheral iridotomy (LPI) rather than a traditional surgical iridectomy. In an LPI, a laser burns a tiny hole through the iris without requiring an incision into the eye. It takes just a few minutes, uses numbing eye drops, and you go home the same day. For acute angle-closure glaucoma, laser iridotomy successfully controls eye pressure in roughly 60 to 71% of eyes when performed within seven days of symptom onset.
Surgical iridectomy, where a surgeon physically cuts and removes a piece of iris, is reserved for situations where laser treatment isn’t possible or hasn’t worked. This includes patients whose corneas are too cloudy for the laser beam to pass through clearly, cases where the iris tissue is too thick for laser penetration, and situations requiring other surgical work on the eye at the same time. In these scenarios, newer techniques using very small instruments (25-gauge aspiration cutters, for example) have made the surgical approach less invasive than it once was.
When an Iridectomy Is Needed
The primary reason for an iridectomy is narrow-angle or angle-closure glaucoma. Your eye doctor identifies this risk using a diagnostic lens called a gonioscope, which lets them see the drainage angle directly. Patients with significant narrowing, adhesions between the iris and the drainage structures (called synechiae) covering 180 degrees or more, or signs that the internal structures of the eye are positioned abnormally forward are at highest risk and most likely to need the procedure.
Iridectomy is also performed as a preventive measure. If one eye has had an acute angle-closure attack, the other eye often has similar anatomy and a high chance of experiencing the same problem. Doctors typically treat the second eye before an attack occurs. Less commonly, iridectomy is used to remove small iris tumors, including certain melanomas confined to the iris.
What the Procedure Feels Like
For a laser iridotomy, you sit at a slit lamp (the same chin-rest device used during routine eye exams). Numbing drops are placed in the eye, and a special contact lens is held against it to focus the laser. You’ll see bright flashes and may feel a brief stinging sensation with each laser pulse. The whole process typically takes under 10 minutes.
Surgical iridectomy requires more preparation. Depending on the complexity and your overall health, you may receive local anesthesia (eye area numbed, but you’re awake), light sedation, or general anesthesia. The surgery itself usually takes less than an hour. You’ll have a patch over the eye afterward and will need someone to drive you home.
Recovery and Aftercare
After either version of the procedure, expect some mild eye pain, sensitivity to light, and blurry vision for a few days. Over-the-counter pain relievers like acetaminophen typically handle any discomfort. Your doctor will prescribe antibiotic and steroid eye drops to prevent infection and control inflammation. These drops are usually needed for several weeks, sometimes up to three months depending on how your eye heals.
Physical restrictions matter more than most patients expect. For the first six weeks after a surgical iridectomy, avoid activities that involve bending forward, heavy lifting, running, jumping, and swimming. Skip eye makeup for at least the first week. Your doctor will check your eye pressure at follow-up visits and let you know when it’s safe to return to full activity. In some cases, if the procedure alone doesn’t bring eye pressure down to the target range, you may need to continue using pressure-lowering eye drops long term.
Risks and Possible Complications
Iridectomy is a well-established procedure, but no surgery is risk-free. The most common complications include:
- Bleeding inside the eye (hyphema): A small amount of bleeding from the cut iris tissue can temporarily cloud vision. This usually resolves on its own within days.
- Elevated eye pressure: A short-term pressure spike can occur in the hours or days after the procedure, requiring additional treatment.
- Cataract formation: The lens sits directly behind the iris, and surgical instruments or laser energy can occasionally damage it, accelerating cataract development over time.
- Corneal damage: Particularly with laser treatment, the inner lining of the cornea can sustain minor injury.
- Glare or visual disturbance: The hole in the iris can let extra light into the eye, causing halos or glare, especially at night. Doctors try to position the opening where the upper eyelid covers it to minimize this effect.
How Success Is Measured
The goal is straightforward: bring eye pressure down to a safe level and keep it there without further intervention. Research on acute angle-closure glaucoma shows that patients whose eye pressure drops by more than 30% with initial medical treatment before the procedure have the best outcomes. In that group, over 90% maintain normal pressure with laser iridotomy alone. Patients who respond less dramatically to initial treatment are more likely to need additional procedures or ongoing medication.
Timing also plays a significant role. Eyes treated within seven days of the onset of an acute attack respond better than those treated later, likely because prolonged high pressure causes lasting damage to the drainage structures. This is why acute angle-closure glaucoma is treated as an emergency, with pressure-lowering medications started immediately and iridectomy scheduled as soon as conditions allow.