Laser Peripheral Iridoplasty (ALPI)
Understanding Narrow Drainage Angles and ALPI
Your eye constantly makes a clear fluid called aqueous humor to keep its shape and nourish internal tissues. This fluid flows from behind your iris, through your pupil, and exits through a drainage angle where your iris meets your cornea. When this system works properly, fluid leaves your eye at the same rate it is produced, keeping eye pressure stable and healthy.
The drainage angle contains a mesh-like structure called the trabecular meshwork that filters fluid out of your eye. If this angle stays wide open, fluid drains easily and eye pressure remains normal.
Some people have eyes that are built in a way that makes the drainage angle very narrow. When the angle becomes too narrow, fluid may not escape properly. In some cases, the angle can close suddenly, causing pressure to build quickly inside your eye, which can damage the optic nerve and cause permanent vision loss.
- Sudden angle closure causes severe eye pain, blurred vision, and headaches
- Gradual narrowing may cause no symptoms until damage occurs
- High eye pressure from a closed angle requires urgent medical attention
- Without prompt treatment, acute angle closure can lead to vision loss
ALPI uses a focused laser beam to create tiny burns on the outer edge of your iris. These controlled burns cause the iris tissue to contract and pull away from the drainage angle. This reshaping creates more space for fluid to flow through, which can lower eye pressure and help reduce the risk of future angle closure.
The procedure targets the peripheral iris, moving it back to open the angle without creating any holes. We often treat multiple spots around the peripheral iris to achieve the desired angle widening.
When ALPI May Be Recommended
We may recommend ALPI for several specific conditions related to narrow or closed drainage angles. ALPI is typically used as an adjunctive treatment rather than a first-line option. Laser peripheral iridotomy, or LPI, is usually the first laser procedure for narrow angles caused by pupillary block, where fluid becomes trapped behind the iris. ALPI is often added when you have plateau iris configuration or when your angle remains narrow even after a patent iridotomy has been performed.
For many patients with primary angle closure related to a thickened lens crowding the angle, lens extraction or cataract surgery is commonly considered for definitive anatomical relief. ALPI may also be used as a temporary measure to widen the angle when an iridotomy cannot be performed immediately, such as when corneal swelling blocks the laser view. One limitation of ALPI is that it may be less effective when there is extensive peripheral anterior synechiae, or PAS, meaning permanent adhesions have already formed between your iris and the drainage angle.
Many people with narrow angles notice no symptoms until an acute attack happens. When symptoms do occur, you might experience halos around lights, especially at night, or mild headaches above your eyebrows. Some patients notice temporary blurring when moving from bright to dim lighting.
- Intermittent eye discomfort or aching
- Rainbow-colored rings around lights
- Headaches that worsen in low light
- Episodes of blurred vision that come and go
Acute angle closure is a vision-threatening emergency that requires immediate medical attention. If you experience sudden, severe eye pain along with extremely blurred vision, nausea, and vomiting, call for emergency care right away. You may also see halos around every light, notice your eye is red, and feel intense headache pain.
Your pupil may appear larger than normal and may not respond to light. These symptoms indicate dangerously high eye pressure that can cause permanent vision loss if not treated promptly.
ALPI is one of several treatment options for narrow angles and angle closure conditions. Our eye doctor will help you understand which approach or combination is best for your situation.
- Laser peripheral iridotomy to create a small hole in the iris for pupillary block
- Medications to lower eye pressure during acute attacks or for ongoing control
- Lens extraction or cataract surgery to widen the angle by removing the crowding lens
- Goniosynechialysis to separate iris adhesions in selected cases
- Ongoing glaucoma drops for chronic pressure management
- Pilocarpine drops to keep the pupil small in select plateau iris cases
- Observation with regular monitoring for narrow angles that have not yet closed
- Surgical options like trabeculectomy or tube shunt for established glaucoma when appropriate
Factors That Increase Your Risk
Farsightedness is one of the strongest risk factors for narrow angles because farsighted eyes tend to be shorter than average from front to back. This shorter shape crowds the internal structures, leaving less room for fluid to drain. A thicker lens or an iris that sits farther forward can also reduce the space available for drainage.
Eyes with a shallower anterior chamber, the space between your cornea and iris, are more likely to develop narrow angles. Some people are simply born with eye anatomy that creates a naturally tight drainage angle.
Your risk of angle closure increases as you age because the natural lens inside your eye grows thicker throughout your life. This gradual thickening pushes the iris forward and narrows the drainage angle over time. Women face higher risk than men because female eyes tend to be smaller on average.
- People over 40 are at increased risk
- Those of East Asian or Inuit descent have higher rates
- Women are affected more often than men
- Family history of angle closure raises your risk
Certain medications can trigger angle closure in people with already narrow angles. Anticholinergic drugs block certain nerve signals and can cause your pupil to dilate and your iris to bunch up and block drainage. These include some cold medicines, antidepressants, anti-nausea medications, and antihistamines. Adrenergic agents that stimulate the nervous system can also dilate the pupil. The medication topiramate can cause a different type of secondary angle closure through choroidal effusion and forward movement of the lens and iris, even without pupil dilation.
Inflammation inside your eye from uveitis or injury can also cause the angle to narrow temporarily or permanently. If you have known narrow angles, consult our eye doctor before starting new medications that can affect your pupil or drainage angle. Let us know about all medications and supplements you take.
Diagnosing Narrow Angles: What to Expect
We begin by measuring your intraocular pressure with a device that gently touches your eye after we apply numbing drops. Elevated pressure may indicate angle closure, though some people have narrow angles with normal pressure. We also check your visual field to see if glaucoma has already affected your peripheral vision.
Visual field testing asks you to look straight ahead and push a button when you see small flashing lights in different areas. This test maps your entire range of vision and helps us detect any damage to your optic nerve.
Gonioscopy is the essential test for diagnosing narrow angles. We place a special contact lens with mirrors on your numbed eye to see the drainage angle directly. This examination tells us exactly how narrow your angle is and whether it is open, partially closed, or completely closed.
- The test is painless and takes only a few minutes
- We can see if your iris is blocking the trabecular meshwork
- Different lighting helps us assess how the angle changes
- Results guide our treatment recommendations
We may use specialized imaging technology to get detailed pictures of your drainage angle. Optical coherence tomography, or OCT, uses light waves to create cross-sectional images of your anterior chamber. Ultrasound biomicroscopy provides high-resolution images of structures behind your iris that we cannot see with direct examination.
These imaging tests help us measure the exact depth of your anterior chamber and the width of your drainage angle. The images also reveal whether certain anatomical features like plateau iris are contributing to angle narrowing.
We typically recommend ALPI in specific situations where other treatments may not be sufficient. The following scenarios are common reasons we may select ALPI for your angle closure condition.
- Plateau iris configuration where the iris sits too far forward despite an open iridotomy
- Persistent narrow angle after a patent laser peripheral iridotomy has been performed
- Temporary angle opening when iridotomy cannot be performed immediately due to corneal edema
- Need for rapid angle widening in selected acute situations alongside medications
- Combination treatment when both pupillary block and iris position contribute to closure
The ALPI Procedure: What You'll Experience
You can eat and drink normally before your ALPI procedure. Bring a list of all your current medications, including eye drops, because we need to know what you are using. Plan to have someone drive you home afterward since your vision may be temporarily blurred from the treatment and the eye drops we use.
Wear comfortable clothing and avoid heavy eye makeup on the day of your procedure. If you wear contact lenses, remove them before your appointment. Let us know if you have any allergies to medications or numbing drops.
We start by placing numbing drops in your eye so you will not feel pain during the laser treatment. We also use drops to make your pupil smaller, which helps us access the peripheral iris more easily. Some patients notice a mild brow ache from these pupil-constricting drops. You will sit at a slit lamp, the same microscope we use for regular eye exams, and rest your chin and forehead against the supports.
- We place a special contact lens on your numbed eye
- The lens helps focus the laser and keeps your eye steady
- You will need to look straight ahead at a target light
- Staying as still as possible helps us work accurately
Our eye doctor uses the laser to deliver small spots of energy to the outer edge of your iris. We typically place spots evenly around the entire circumference of the iris, creating a ring of treatment. Each application lasts only a fraction of a second, and we treat multiple locations to achieve the desired reshaping effect.
The laser energy causes controlled contraction of iris tissue, which pulls the peripheral iris away from the drainage angle. The entire treatment usually takes about 10 to 15 minutes, though this can vary depending on how much of your iris needs treatment.
During the procedure, you will hear a clicking sound each time the laser fires. You may see bright flashes of colored light with each laser application. Most patients describe feeling only slight discomfort or a mild poking sensation, but no sharp pain because of the numbing drops.
Some people notice a slight warming sensation or pressure during treatment. Your vision will be blurry both from the contact lens and the laser effects, but this clears after we remove the lens. Any discomfort during the procedure is brief and manageable.
Recovery and Follow-Up Care
We will prescribe anti-inflammatory eye drops to use for several days after your procedure to reduce swelling and discomfort. You may also need to continue or start pressure-lowering eye drops depending on your specific situation. Use all medications exactly as directed to ensure proper healing and pressure control.
- Apply drops at the scheduled times without missing doses
- Wash your hands before touching your eye or bottles
- Wait five minutes between different eye drop medications
- Store medications properly and check expiration dates
- Call us if you have questions about your drop schedule
Most people can return to normal activities the day after ALPI, but our office typically recommends you avoid strenuous exercise, heavy lifting, and activities that strain your eyes for at least a few days. Do not rub your treated eye even if it feels irritated. Protect your eye from dust, dirt, and wind by wearing sunglasses when outdoors.
You can shower and wash your face gently, but keep soap and water out of your treated eye for the first few days. Our general guidance is to avoid swimming, hot tubs, and saunas for at least one week to reduce infection risk. Ask our eye doctor when you can safely resume wearing eye makeup or contact lenses.
As with any laser procedure, ALPI carries certain risks that we will discuss with you before treatment. Most complications are mild and temporary, but you should be aware of what might occur.
- Transient spike in eye pressure shortly after the procedure
- Inflammation or iritis requiring additional anti-inflammatory drops
- Pain, photophobia, or light sensitivity for a few days
- Temporary blurred vision beyond the immediate post-procedure period
- Corneal epithelial defect or minor corneal burn
- Iris atrophy or focal thinning at treatment spots
- Pupil distortion or irregular pupil shape
- Progression of peripheral anterior synechiae
- Need for repeat ALPI treatment
- Incomplete response requiring additional procedures or surgery
We commonly check your eye pressure shortly after the laser procedure, often within 30 to 60 minutes, to ensure there is no pressure spike. For higher-risk angle closure patients, we may recommend additional early follow-up the same day or the next day to monitor both pressure and inflammation. We also schedule a follow-up visit within one to two weeks after ALPI to check your eye pressure and examine the drainage angle with gonioscopy to confirm that the angle has widened as intended.
At each visit, we measure your eye pressure, check for inflammation, and assess your vision. We also monitor for any complications and determine whether you need additional treatment. Some patients require ongoing glaucoma medications even after successful ALPI, while others may need further laser or surgical procedures if the angle remains too narrow.
Contact us right away if you experience severe eye pain, a sudden decrease in vision, or intense headache after your procedure. Worsening redness, discharge from your eye, or increasing sensitivity to light may signal infection or inflammation that needs treatment. If you see new floaters or flashes of light, this could indicate a retinal problem requiring urgent evaluation.
Sudden onset of nausea and vomiting along with eye discomfort might mean your pressure is rising again. Any symptom that seems unusual or concerning deserves a call to our office so we can determine whether you need to be seen immediately.
Frequently Asked Questions
The numbing drops we use prevent pain during ALPI, though you may feel mild pressure or warmth. Afterward, your eye might feel scratchy or mildly sore for a day or two, similar to having an eyelash in your eye. Over-the-counter pain relievers and the anti-inflammatory drops we prescribe usually manage any discomfort easily.
Your vision will be blurry immediately after the procedure from the contact lens and treatment effects, but this typically clears within a few hours. Most patients notice no long-term change in their vision quality from ALPI itself. However, the underlying condition that required ALPI may affect your vision if it has already caused glaucoma damage.
The iris reshaping happens immediately during the laser treatment, but the full effect on angle width may develop over several days as inflammation resolves. We can usually assess how well the procedure worked at your follow-up visit one to two weeks later. Eye pressure often improves within the first day, though some patients need additional time or treatment.
If your drainage angle remains too narrow after ALPI, we have several options to protect your vision. We may recommend a second ALPI session to treat additional areas of your iris. Some patients benefit from combining ALPI with medications that keep the pupil small to help maintain angle opening. If laser treatments are not sufficient, we may discuss surgical options like lens removal or trabeculectomy to create new drainage pathways.
The iris reshaping from ALPI can be long-lasting, but the natural aging process may cause your lens to thicken and narrow the angle again over time. Some patients maintain adequate angle width for many years, while others need repeat treatments. Your individual eye anatomy, the underlying cause of angle narrowing, and how well you respond to the initial treatment all influence how long the effects last.
Laser peripheral iridotomy creates a tiny hole in the iris to allow fluid to bypass a pupil block, while ALPI reshapes the iris to physically widen the drainage angle. Iridotomy is usually the first-line laser treatment for narrow angles caused by pupil block, whereas we add or substitute ALPI when the angle remains narrow despite having an iridotomy. Some conditions like plateau iris respond better to ALPI because the problem is iris position rather than fluid flow behind the iris.
Getting Help for Laser Peripheral Iridoplasty
If you have been diagnosed with narrow drainage angles or have experienced symptoms of angle closure, our eye doctor can evaluate whether ALPI is right for you. We will perform a thorough examination, discuss your treatment options, and create a plan to protect your vision.