Laser iridotomy is a common, non-invasive procedure used to create a small opening in the iris, the colored part of the eye. This treatment aims to relieve pressure buildup in specific types of glaucoma. By creating a new pathway for fluid to circulate within the eye, the procedure lowers the intraocular pressure (IOP) that can cause irreversible damage to the optic nerve. This quick, office-based laser treatment serves as a preventative measure or a treatment for the immediate pressure spike associated with angle-closure glaucoma.
Understanding Angle-Closure Glaucoma
This laser procedure addresses the mechanical problem found in angle-closure glaucoma (narrow-angle or closed-angle glaucoma). The eye constantly produces aqueous humor, which must drain through the trabecular meshwork, located in the angle between the iris and the cornea. In a healthy eye, this fluid flows freely from the posterior chamber, through the pupil, and into the anterior chamber before reaching the drainage angle.
In angle-closure glaucoma, “pupillary block” occurs when the iris presses against the lens, blocking the normal flow of aqueous humor through the pupil. This blockage causes fluid to accumulate in the posterior chamber, pushing the peripheral iris forward. The forward-pushed iris then physically obstructs the trabecular meshwork, closing the drainage angle.
When the drainage angle is blocked, aqueous humor cannot exit the eye, leading to a rapid increase in intraocular pressure (IOP). This pressure spike can happen suddenly in an acute attack or gradually over time, causing progressive damage to the optic nerve. The laser iridotomy bypasses the pupillary block, preventing the iris from pushing forward and closing the drainage system. This procedure eliminates the mechanical component of the disease, normalizing fluid dynamics and safeguarding vision.
How the Laser Iridotomy Procedure Works
Laser iridotomy is typically performed in an ophthalmologist’s office or outpatient clinic and usually takes less than 10 minutes. The procedure utilizes a YAG laser, which delivers a high-energy, focused beam of light to the iris tissue. Only topical anesthetic drops are applied to numb the eye’s surface; no injections or incisions are necessary.
Before the laser is applied, a special contact lens is often placed on the eye to help focus the laser beam precisely onto the peripheral iris and stabilize the eye. The surgeon uses the laser to create a microscopic opening in the top outer edge of the iris. This tiny hole acts as a permanent bypass, allowing the aqueous humor to flow directly from the posterior chamber to the anterior chamber, entirely circumventing the pupil.
During the treatment, the patient sits upright at a machine similar to a standard eye examination slit lamp and may see a bright flash of light with each laser pulse. Patients may report a mild stinging sensation or a brief pinch, though the procedure is largely painless due to the numbing drops. The creation of this new channel instantly relieves the pressure differential between the two chambers, pulling the peripheral iris back and away from the drainage angle.
What to Expect Before and After the Treatment
Preparation begins with a consultation where the eye doctor explains the procedure and obtains informed consent. On the day of the procedure, patients receive several types of eye drops, including a topical anesthetic to numb the eye. A miotic agent, such as pilocarpine, is also administered to constrict the pupil, which helps stretch and thin the iris, making it easier for the laser to create the opening.
Immediately after the treatment, the eye pressure is checked to ensure it has not spiked significantly, which can sometimes occur temporarily. Patients may experience a brief period of blurred vision, mild eye irritation, or increased sensitivity to light due to the bright lights and eye drops used. These short-term effects are mild and resolve within a few hours to a day.
To manage inflammation caused by the laser, the doctor will prescribe anti-inflammatory steroid eye drops, typically used for one to two weeks. Although there are usually no physical restrictions on activity, patients are advised to have someone drive them home, as vision may be temporarily blurred. A follow-up appointment is scheduled shortly after the procedure to check the eye pressure and confirm the new opening is functioning correctly.
Possible Complications and Long-Term Care
Laser iridotomy is generally a safe procedure, but some potential side effects and complications can occur, though they are uncommon. A transient spike in intraocular pressure is the most frequent adverse event immediately following treatment. This is why pressure is checked before the patient leaves and is usually managed with extra pressure-lowering drops. Mild bleeding from the iris at the treatment site is also possible, but this typically stops quickly and resolves on its own.
Some patients report visual disturbances, such as glare, halos, or a “ghost image” (dysphotopsia), especially in dim light. This is caused by light passing through the new opening. This effect is rare and often improves over several months as the brain adjusts, though it can occasionally be a long-term issue. Inflammation of the eye (uveitis) can also occur but is controlled with the prescribed anti-inflammatory drops.
For long-term care, the iridotomy is considered a permanent opening, but follow-up appointments are necessary to ensure the hole remains patent and has not closed over with tissue. While the procedure eliminates the pupillary block mechanism, it does not always completely cure the glaucoma. Many patients still require ongoing monitoring and may need to continue using glaucoma eye drops or require future surgical intervention if other forms of glaucoma are present or if eye pressure is not fully controlled.