Laser iridotomy is a quick outpatient procedure where an eye doctor uses a laser to create a tiny hole in the iris, the colored part of your eye. The hole allows fluid to flow freely between the two chambers inside your eye, relieving pressure buildup that can damage your optic nerve and lead to a type of glaucoma called angle-closure glaucoma.
How It Works
Your eye constantly produces a clear fluid called aqueous humor, which nourishes the lens and cornea before draining out through a mesh-like channel at the angle where your iris meets the cornea. In some people, the iris sits too far forward, physically blocking that drainage channel. When fluid can’t escape, pressure inside the eye rises, sometimes gradually and sometimes in a sudden, painful spike.
The laser creates a microscopic opening in the outer edge of the iris. This opening acts as an alternate pathway for fluid, equalizing the pressure between the back chamber (behind the iris) and the front chamber (in front of the iris). Once pressure equalizes, the iris settles back into a flatter position and the drainage angle opens up. Think of it like poking a small vent in a sealed room so air can circulate instead of building up on one side.
Who Needs It
The most common reason for laser iridotomy is anatomically narrow drainage angles, a condition that puts you at risk for angle-closure glaucoma. Your eye doctor can detect this during a routine exam using a special lens to inspect the drainage angle directly. People with narrow angles who haven’t developed glaucoma yet are called “primary angle-closure suspects,” and iridotomy is often recommended as a preventive measure.
Iridotomy is also used as an emergency treatment during an acute angle-closure attack, when the drainage angle suddenly closes off entirely. Symptoms of an acute attack include severe eye pain, headache, nausea, blurred vision, and seeing halos around lights. This is a medical emergency that can cause permanent vision loss within hours if the pressure isn’t relieved.
People of East Asian descent, women, and those who are farsighted tend to have shallower anterior chambers, making them more likely candidates for the procedure.
How Effective It Is Long-Term
A landmark 14-year study known as the Zhongshan Angle-Closure Prevention Study tracked people identified as angle-closure suspects in a community setting. Those who received laser iridotomy had roughly a two-thirds lower rate of progressing to actual angle-closure glaucoma compared to untreated eyes. The treated eyes were about 69% less likely to develop the condition over the study period. That’s a significant reduction in risk from a procedure that takes minutes and requires no incisions.
It’s worth noting that iridotomy works best when the primary problem is the iris blocking the drainage angle. In some cases, other structures in the eye contribute to angle narrowing, and additional treatment may be needed.
What the Procedure Feels Like
The entire procedure takes only a few minutes per eye. Before starting, your doctor will apply several rounds of eye drops. One set constricts your pupil, pulling the iris taut so the laser can create a clean opening. Another drop helps prevent a temporary pressure spike. A numbing drop ensures you won’t feel pain.
You’ll sit at a slit lamp, the same chin-rest microscope used during a standard eye exam. The doctor places a small contact lens on your eye to focus the laser beam and keep your eyelid open. You’ll see bright flashes of light and may feel a brief stinging or snapping sensation, but it’s not painful. Most people describe it as mildly uncomfortable rather than distressing. You won’t need sedation or an IV, and you can go home shortly after.
Recovery and Aftercare
Your vision will be blurry for a few hours after the procedure, and your eye may feel slightly irritated or light-sensitive. Most doctors prescribe anti-inflammatory eye drops to use three to four times daily for about four to seven days to control any post-procedure inflammation. You’ll typically have a follow-up appointment within one to two weeks so your doctor can check the opening and measure your eye pressure.
Most people return to normal activities the next day. There’s no surgical wound to heal, no stitches, and no patch. You should avoid rubbing your eye for a day or two, but otherwise daily life resumes quickly.
Risks and Side Effects
Laser iridotomy has a strong safety profile, but no procedure is completely without risk. The most commonly reported side effects are visual disturbances. In a study published by the American Academy of Ophthalmology, about 8.9% of patients reported at least one new visual symptom after the procedure. The most frequent complaints were glare (4.3%), mild blurring (4.3%), and seeing faint horizontal lines (2.7%). These symptoms are caused by light entering through the new opening in the iris and are more noticeable in certain lighting conditions. For most people, the symptoms are mild and either resolve over time or become easy to ignore.
A temporary spike in eye pressure can occur in the first hour or two after treatment. Research shows that about 9.8% of treated eyes experience a noticeable pressure elevation at the one-hour mark, but this drops to less than 1% by two weeks. Fewer than 1% of eyes reach a pressure level high enough to require immediate medical treatment. The pre-procedure drops your doctor uses are specifically designed to minimize this risk, and your pressure is checked before you leave the office.
Rare complications include minor bleeding inside the eye (which usually stops on its own within seconds), inflammation that persists longer than expected, or, very uncommonly, the opening closing over time and requiring a repeat procedure.
Iridotomy vs. Other Glaucoma Treatments
Laser iridotomy specifically addresses the mechanical problem of a crowded drainage angle. It’s different from other common glaucoma laser procedures. Selective laser trabeculoplasty, for example, targets the drainage mesh itself to help it filter fluid more efficiently, and is used primarily in open-angle glaucoma where the angle is wide but the mesh isn’t draining well. Pressure-lowering eye drops, meanwhile, either reduce fluid production or increase outflow but don’t change the underlying anatomy.
If you’ve been told you have narrow angles, iridotomy is typically the first-line treatment because it addresses the root structural issue rather than just managing pressure with daily medication. For people already diagnosed with angle-closure glaucoma and optic nerve damage, iridotomy is usually performed alongside other treatments like pressure-lowering drops or additional laser or surgical procedures.