Laser Peripheral Iridoplasty (ALPI)
What Is Laser Peripheral Iridoplasty
Laser peripheral iridoplasty, also known as argon laser peripheral iridoplasty (ALPI), is a specialized in-office laser procedure used to widen the drainage angle inside the eye. When the drainage angle becomes too narrow or closes, fluid cannot exit the eye properly, leading to elevated eye pressure and potential optic nerve damage. At Greenwich Ophthalmology Associates, our glaucoma specialists use ALPI to treat angle-closure conditions that do not fully respond to other interventions, helping patients across the greater NY/CT region protect their vision through precise, targeted care.
Laser peripheral iridoplasty is a glaucoma laser procedure that reshapes the peripheral iris to improve fluid drainage within the eye. Understanding how this treatment fits into the broader landscape of angle-closure management can help you make informed decisions about your care.
The drainage angle is the area where the iris meets the cornea at the front of the eye. This narrow channel contains the trabecular meshwork, a sponge-like tissue that filters aqueous humor (the clear fluid inside the eye) out of the eye and into the bloodstream. When the peripheral iris pushes forward and blocks this channel, intraocular pressure (IOP) rises because fluid has nowhere to go. Over time, elevated pressure can damage the optic nerve and lead to glaucoma-related vision loss.
While selective laser trabeculoplasty (SLT) targets the trabecular meshwork directly to improve drainage, and laser peripheral iridotomy (LPI) creates a small opening in the iris to relieve pressure buildup behind it, ALPI works differently. During iridoplasty, the laser is applied to the far peripheral surface of the iris itself. The energy causes the iris tissue to contract and thin, physically pulling it away from the drainage angle. This makes ALPI uniquely suited for situations where the angle remains narrow or closed even after an iridotomy has been performed.
ALPI is used for several angle-closure conditions. These include plateau iris syndrome, acute angle-closure attacks, phacomorphic angle closure related to an enlarged lens, and angle narrowing caused by certain iris or ciliary body cysts. It can also serve as a bridge treatment to lower eye pressure quickly while other definitive procedures are being planned.
How Laser Peripheral Iridoplasty Works
The ALPI procedure uses carefully calibrated laser energy to reshape the peripheral iris without creating an opening in the tissue. Here is what happens during and immediately after treatment.
Before the procedure begins, our glaucoma specialists place numbing drops in the eye to ensure comfort. A special contact lens, called an Abraham or Wise iridoplasty lens, is then placed on the eye's surface to focus the laser beam and provide a clear view of the peripheral iris. Using an argon laser, the doctor delivers approximately 20 to 40 spots of low-power, long-duration energy in a ring pattern around the outermost edge of the iris. Each spot is carefully placed as far peripherally as possible for the best effect, using a large spot size to gently contract the tissue rather than cut it.
When the laser energy contacts the iris tissue, it causes collagen fibers in the iris stroma to contract and shrink. This contraction physically pulls the peripheral iris away from the trabecular meshwork, widening the drainage angle. Research has also shown that ALPI thins the cross-sectional iris tissue at the treated areas, further reducing the tissue bulk that crowds the angle. The combined effect of contraction and thinning opens the drainage pathway and allows aqueous humor to flow more freely out of the eye.
The entire procedure typically takes 10 to 15 minutes per eye. Mild inflammation is expected, and our glaucoma specialists may prescribe anti-inflammatory eye drops for several days afterward. A brief pressure check is usually performed about 30 to 60 minutes after treatment to ensure the eye is responding well. Most patients can resume normal activities the same day or the following day, though your doctor will provide specific guidance based on your situation.
Who Is a Good Candidate for Laser Peripheral Iridoplasty
ALPI is not a first-line treatment for every form of glaucoma. It is specifically indicated when certain anatomical or clinical conditions prevent the drainage angle from opening through other means.
Plateau iris syndrome is one of the most common reasons for ALPI. In this condition, the iris root is positioned abnormally forward due to anteriorly rotated ciliary processes pushing the peripheral iris against the drainage angle. Because this type of angle closure is not caused by pupillary block, a standard laser iridotomy alone cannot fully resolve it. ALPI contracts the peripheral iris tissue to pull it away from the angle, addressing the underlying mechanism directly. Long-term studies have shown that ALPI can maintain open angles in plateau iris patients for many years, though a small number may eventually require retreatment.
During an acute angle-closure crisis, eye pressure rises rapidly and can cause severe pain, nausea, blurred vision, and halos around lights. While medications and laser iridotomy are typically the primary treatments, ALPI can be used as an emergency adjunct when the cornea is too swollen or cloudy to perform an iridotomy safely. Studies have shown that ALPI can lower eye pressure significantly faster than medication alone during an acute attack, providing rapid relief while the cornea clears enough for additional treatment.
Some patients undergo a laser peripheral iridotomy and find that their drainage angle remains partially or fully closed. This can happen when non-pupillary block mechanisms, such as a thick or bulky peripheral iris, contribute to angle crowding. In these cases, ALPI can serve as a second-line procedure to mechanically widen the angle and improve the effectiveness of prior laser treatment.
ALPI may also benefit patients with angle closure related to nanophthalmos (an unusually small eye), phacomorphic glaucoma caused by a swollen or enlarged lens, or certain types of secondary angle closure. It is sometimes performed before SLT laser treatment to widen a narrow angle enough to safely access the trabecular meshwork. Our glaucoma specialists evaluate each patient's anatomy using gonioscopy and anterior segment imaging to determine whether ALPI is the right approach.
Benefits of Laser Peripheral Iridoplasty
ALPI offers several practical advantages for patients with angle-closure conditions. Understanding these benefits can help you weigh your treatment options with confidence.
Unlike incisional glaucoma surgeries such as trabeculectomy or tube shunt placement, ALPI is performed in the office using only topical numbing drops. There are no surgical incisions, sutures, or operating room requirements. This means a shorter procedure time, minimal disruption to your daily routine, and a lower overall risk profile compared to traditional glaucoma surgery.
In acute angle-closure situations, time is critical. ALPI has been shown to lower eye pressure more quickly than medical therapy alone. In clinical studies, patients treated with ALPI during an acute attack achieved target pressure levels in under 20 minutes on average, compared to nearly two hours with medication alone. This rapid response can help protect the optic nerve during a pressure crisis.
Because ALPI does not alter the trabecular meshwork or create permanent drainage pathways, it preserves the eye's anatomy for future procedures if they become necessary. Patients who undergo ALPI remain candidates for SLT, minimally invasive glaucoma surgery (MIGS), cataract extraction with angle-based procedures, or traditional filtration surgery. This flexibility is an important consideration in the long-term management of angle-closure glaucoma.
Frequently Asked Questions
ALPI is generally considered a safe procedure. The most common side effects include mild eye inflammation, a temporary spike in eye pressure immediately after treatment, and minor discomfort or light sensitivity for a day or two. Rare complications can include localized iris burns, slight pupil distortion, or corneal endothelial cell damage if the laser energy is applied too close to the cornea. Our glaucoma specialists use careful technique and appropriate laser settings to minimize these risks.
No special preparation is typically required. You should continue taking all of your current eye medications unless your doctor instructs otherwise. Because your pupils do not usually need to be dilated for ALPI, most patients find that their vision returns to normal relatively quickly after the procedure. We recommend arranging a ride home, as your vision may be slightly blurry from the contact lens and numbing drops used during treatment.
In many patients, a single ALPI session provides long-lasting results. However, in some cases, particularly with plateau iris syndrome, the angle may gradually re-narrow over several years. Studies tracking patients for up to a decade have found that a small percentage require one repeat treatment to maintain an open angle. Your doctor will monitor your drainage angle at regular follow-up visits and recommend retreatment only if needed. You can learn more about what follow-up entails in our glaucoma surgery recovery guide.
Laser peripheral iridotomy (LPI) creates a tiny hole through the iris to allow fluid to flow from behind the iris to the front chamber, relieving a pressure difference called pupillary block. ALPI does not create a hole. Instead, it reshapes and contracts the peripheral iris surface so that the tissue physically moves away from the drainage angle. The two procedures treat different mechanisms of angle closure and are often used in sequence when iridotomy alone does not fully open the angle.
ALPI is a medically necessary procedure when performed for documented angle-closure conditions, and most insurance plans, including Medicare, typically cover it. Coverage generally requires a confirmed diagnosis of angle closure, plateau iris syndrome, or a related condition. Our team can help verify your specific benefits before scheduling the procedure.
Yes. ALPI is frequently performed in combination with or following a laser peripheral iridotomy. It can also be used before SLT in patients whose angles are too narrow for safe trabeculoplasty. In patients with coexisting cataracts, ALPI may serve as a temporizing measure to control pressure while cataract surgery is planned. The approach our glaucoma specialists recommend depends on your specific anatomy, pressure levels, and overall treatment goals.
Protect Your Vision with Expert Glaucoma Care
Angle-closure conditions require prompt, precise treatment to preserve your sight, and laser peripheral iridoplasty is one of several effective tools available to address them. At Greenwich Ophthalmology Associates, our fellowship-trained glaucoma specialists bring decades of experience in advanced laser and surgical techniques to patients throughout the greater NY/CT region. If you have been diagnosed with angle closure, plateau iris, or elevated eye pressure, we are here to help you find the right path forward for your vision.
We encourage you to bring your questions and concerns to your next appointment so we can develop a care plan that addresses your goals and lifestyle.
Learn More About Related Topics
To further your understanding, explore our resources on Laser Peripheral Iridotomy (LPI) for Glaucoma, Glaucoma Treatment Options: Drops, Laser and Surgery, and Peripheral Vision Loss: Causes & Glaucoma Connection.
You may also find these pages helpful: SLT Laser: A First-Line Alternative to Eye Drops, Angle-Closure Glaucoma: Recognizing the Emergency, and Angle-Closure Glaucoma: Symptoms & Emergency Treatment.
What our Patients say
4.8
Reviews
(3547)