Laser Peripheral Iridotomy (LPI)
A quick, well-established laser procedure that relieves pupillary block and reduces the risk of a dangerous angle-closure attack in eyes with narrow or closed drainage angles.
What Is Laser Peripheral Iridotomy?
Laser peripheral iridotomy (LPI) uses a laser to create a small, full-thickness opening in the peripheral iris (the colored part of the eye). This opening gives fluid inside the eye a second route to pass from behind the iris to the front chamber, equalizing pressure between the two spaces and relieving pupillary block — the mechanism behind most narrow-angle and angle-closure glaucoma.
How It Works & What to Expect
- Performed in the office using numbing eye drops; a pressure-lowering drop is often given beforehand
- A special contact lens focuses the laser on a chosen spot in the peripheral iris, usually positioned under the upper eyelid
- The procedure typically takes just a few minutes per eye
- Pressure is checked shortly after the procedure, since a temporary spike can occur
- Most patients resume normal activity the same day
Indications
- ✓Anatomically narrow angles at meaningful risk of future closure, identified on gonioscopy
- ✓Treatment of an acute angle-closure attack, once the cornea is clear enough to allow the laser to be performed safely
- ✓Prophylactic treatment of the unaffected fellow eye after a unilateral acute angle-closure attack
- ✓Chronic angle-closure glaucoma, as part of a broader treatment plan
- ✓A component of managing combined mechanism glaucoma, where relieving pupillary block is the first step
Alternatives
Laser peripheral iridoplasty is a related but distinct laser procedure used specifically for plateau iris configuration, where the angle stays crowded even after a patent iridotomy; it shrinks the peripheral iris tissue itself rather than creating an opening through it. Clear lens extraction (cataract surgery) is a well-studied alternative, and for some patients a superior one: the EAGLE trial, a randomized controlled trial published in The Lancet in 2016, found that early lens extraction produced better eye pressure control and was more cost-effective than laser iridotomy for primary angle-closure glaucoma with elevated eye pressure.1 We discuss both LPI and lens extraction individually based on each patient's anatomy, cataract status, and preferences — see our Cataract Surgery for Glaucoma page.
Risks & Side Effects
- ✓A temporary rise in eye pressure in the hours after treatment
- ✓Mild inflammation or light sensitivity for a day or two
- ✓Small amount of bleeding at the treatment site, which typically stops on its own during the procedure
- ✓Glare, halos, or a faint line of light from the opening, particularly if it isn't fully covered by the eyelid — uncommon but possible
- ✓Rarely, a small, usually visually insignificant effect on the adjacent lens (cataract progression) or cornea
Benefits
LPI is a fast, well-tolerated, and highly effective procedure at relieving pupillary block and substantially lowering the risk of a future acute angle-closure attack, which is a genuine ocular emergency that can cause rapid, severe, and permanent vision loss if not treated promptly. For most patients with narrow but not yet closed angles, LPI is a preventive, one-time (or two-eye) procedure rather than an ongoing treatment.
References
- Azuara-Blanco A, Burr J, Ramsay C, et al. Effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE): a randomised controlled trial. Lancet. 2016;388(10052):1389-1397.
Frequently Asked Questions
Does LPI hurt?
No. LPI is performed with numbing drops only and most patients feel little more than brief pressure or a flash of light during the procedure, which takes just a few minutes.
Will I see a hole in my iris afterward?
The opening is very small and is positioned under the upper eyelid whenever possible so it isn't visually noticeable. Some patients notice a subtle line, crescent, or halo of light from certain angles, especially in bright conditions.
Do I need LPI in both eyes?
Often, yes. If one eye has had an acute angle-closure attack, the fellow eye is at significant future risk and prophylactic LPI is generally recommended for it as well, even if it hasn't had symptoms.
Is LPI the only option for narrow angles?
No. Cataract surgery (lens extraction) is a well-studied alternative, and in some patients a better one — the EAGLE trial found it outperformed laser iridotomy for angle closure with elevated eye pressure. We discuss both options individually with each patient.
See a glaucoma specialist. Dr. Robert Gunzenhauser is Harvard-educated and UCLA fellowship-trained in glaucoma, providing expert diagnosis and treatment for Laser Peripheral Iridotomy at Inland Glaucoma Center in Upland, CA.