Argon Laser Trabeculoplasty
What Is Argon Laser Trabeculoplasty?
Inside your eye, fluid called aqueous humor flows in and out through a mesh-like drain called the trabecular meshwork. When this drain becomes clogged or less efficient, fluid builds up and pressure rises, which can damage the optic nerve in glaucoma. ALT uses a laser to place tiny burns along part of the trabecular meshwork, creating small changes that help the drain work better.
The laser treatment triggers a healing response that opens up drainage channels and allows fluid to exit more easily. Over several weeks, this process lowers the pressure inside your eye, helping protect your optic nerve from further damage.
We may recommend ALT for patients with open-angle glaucoma or ocular hypertension whose eye pressure is not well controlled on medications. It can also be a good choice if you have difficulty taking eye drops every day or if you experience side effects from glaucoma medications. Some patients prefer ALT because it may reduce the number of drops they need. ALT often works well in eyes with a pigmented trabecular meshwork, although the risk of a short-term pressure spike may be higher in heavily pigmented angles.
- Patients with open-angle glaucoma not fully controlled by drops
- People who have trouble remembering or using eye drops daily
- Individuals who experience bothersome side effects from glaucoma medications
- Patients seeking to reduce their medication burden
As of 2025, selective laser trabeculoplasty, or SLT, is more commonly recommended than ALT because it causes less tissue damage and can often be repeated more easily. However, we may still consider ALT in specific cases where it fits your treatment plan. Our eye doctor will explain whether ALT or another laser option offers the best balance of effectiveness, safety, and cost for your unique situation.
We also weigh ALT against adding more eye drop medications, changing to different drops, or moving toward surgical options like trabeculectomy or tube shunts, or minimally invasive glaucoma surgery (MIGS), particularly when combined with cataract surgery. The right choice depends on how high your pressure is, how fast your glaucoma is progressing, and your overall health.
You may be a good candidate for ALT if you have open-angle glaucoma with visible trabecular meshwork and your eye pressure needs better control. Our eye doctor will check your drainage angle during an exam to confirm it is open and accessible for laser treatment. Patients with narrow or closed angles are not suitable for ALT because the laser cannot reach the drainage tissue safely.
- Open drainage angles visible on examination
- Diagnosis of open-angle glaucoma or ocular hypertension
- Eye pressure above target despite current treatment
- Willingness to continue follow-up care and monitoring
ALT is not appropriate in some situations because it will not be effective or may carry higher risk.
- Neovascular glaucoma
- Active uveitis or recent significant intraocular inflammation
- Angle recession from trauma or developmental angle anomalies
- Extensive peripheral anterior synechiae that block access to the trabecular meshwork
- Corneal edema or scarring that prevents a clear view of the angle
Preparing for Your ALT Procedure
Before scheduling your ALT, we will perform several tests to make sure the procedure is safe and likely to help. These include measuring your eye pressure, examining your optic nerve, checking your drainage angle with a special mirrored lens called a gonioscopy lens, measuring your corneal thickness (pachymetry) to help interpret pressure readings, and often optical coherence tomography of the optic nerve and nerve fiber layer. We may also photograph your optic nerve and perform visual field testing to document the current state of your glaucoma.
These baseline measurements help us track your progress after treatment and decide if additional steps are needed. We will discuss your test results with you and answer any questions about what to expect.
- Baseline IOP measured on more than one visit when possible
- Gonioscopy to confirm an open, visible trabecular meshwork
- Central corneal thickness (pachymetry)
- Optic nerve imaging and visual field testing for baseline status
Tell our team about all the medications you take, including prescription drugs, over-the-counter products, and supplements. Do not stop blood thinners or antiplatelet medicines unless we or your prescribing clinician specifically instruct you to do so; ALT usually does not require stopping these medications. However, some blood thinners or anti-inflammatory drugs may need special consideration, so we need a complete list.
- Examples: warfarin, apixaban, rivaroxaban, dabigatran, aspirin, clopidogrel
- Continue glaucoma drops unless we advise a change
- Tell us if you have had a steroid-induced eye pressure rise in the past
ALT is an outpatient procedure done right in our office, so you will go home the same day. Because we use numbing drops and a special contact lens during treatment, your vision may be blurry for a short time afterward. Plan to have someone drive you home, and avoid scheduling important tasks or meetings immediately after your appointment.
Wear comfortable clothing and avoid heavy eye makeup on the day of your procedure. Bring your current glaucoma eye drops with you so we can review your schedule and give you clear instructions for the days ahead.
What to Expect During Argon Laser Trabeculoplasty
When you arrive, we will place numbing drops in your eye so you do not feel pain during the laser treatment. These drops take a few minutes to work fully. You will sit upright at a laser machine that looks similar to the microscope we use for regular eye exams.
Our eye doctor will place a special mirrored contact lens on your eye to view your drainage angle clearly and focus the laser precisely on the trabecular meshwork. The lens may feel a bit unusual, but the numbing drops keep you comfortable throughout the procedure.
Once everything is in position, our eye doctor will aim the argon laser at the trabecular meshwork inside your eye. You will see a bright light and may notice flashes as each laser spot is applied. We typically treat half of the drainage angle in one session and may treat the other half weeks or months later if needed.
- The laser delivers small, controlled burns to the drainage tissue
- Each burn is placed carefully around part of the angle
- You remain seated and keep your head steady against a rest
- Our eye doctor monitors your eye continuously during treatment
A typical session treats about 180 degrees of the angle with a series of small laser spots; the other half may be treated later if needed.
The actual laser treatment usually takes between five and ten minutes for one eye. Including time for numbing drops, positioning, and a brief pressure check afterward, your total visit may last about an hour. Most patients are surprised at how quick and straightforward the process is.
If both eyes need treatment, we generally schedule them on separate days to reduce the risk of pressure spikes and make recovery easier for you.
Because of the numbing drops, you should not feel pain during ALT. Some patients report a mild sensation of pressure from the contact lens or brief pinpricks of light as the laser fires. You may hear soft clicking sounds as the laser pulses.
After the lens is removed, your eye may feel slightly irritated or scratchy for a few hours, similar to having an eyelash in your eye. This feeling usually fades quickly as the numbing drops wear off.
You may be given an over-the-counter pain reliever plan in advance if you are sensitive to light or discomfort.
Recovery and Aftercare Following ALT
Right after your procedure, we will check your eye pressure about 30 to 60 minutes later to make sure it has not spiked. To reduce the risk of a spike, we usually place a pressure-lowering drop before or after the laser, and in some cases we may prescribe a dose of oral acetazolamide. You can go home soon after, but your vision may be hazy or your eye may feel slightly sore for the rest of the day.
- Avoid rubbing or pressing on your treated eye
- Use any prescribed anti-inflammatory drops as directed
- Rest your eyes and avoid strenuous activities for the evening
- Wear sunglasses if bright light bothers you
Continue your regular glaucoma drops exactly as before unless we tell you otherwise. We typically prescribe a short course of an anti-inflammatory drop, such as a steroid or an NSAID, for a few days to reduce irritation. If you have had a steroid-related pressure rise in the past, tell us so we can tailor your regimen.
- Use anti-inflammatory drops as directed, usually for 3 to 5 days
- Space different drops by at least 5 minutes
- Do not change or stop glaucoma medications on your own
We will adjust your treatment plan at your follow-up visits based on how your eye responds.
Most patients can return to normal daily activities the day after ALT. However, we recommend avoiding heavy lifting, straining, or vigorous exercise for a few days to keep pressure stable while your eye heals. You can read, watch television, use a computer, and do light household tasks as long as they feel comfortable.
Wait at least 48 hours before swimming or using hot tubs, and keep soap and water out of your treated eye during showers. If you wear contact lenses, ask our team when it is safe to resume wearing them.
We will schedule a follow-up appointment within the first week or two after your ALT to check your eye pressure and see how your eye is healing. Additional visits over the next few months let us track the effectiveness of the treatment and decide if any changes to your medications are needed. Regular monitoring is essential because glaucoma is a lifelong condition.
- First same-day pressure check in clinic or within one to two weeks, depending on your pressure and risk level
- Follow-up at four to six weeks
- Ongoing visits every few months as needed
- Adjustments to drops based on pressure trends
- Extra early checks may be needed if you have advanced glaucoma or only one seeing eye
The pressure-lowering effect of ALT does not happen immediately. It usually takes four to six weeks for the full benefit to appear as your drainage system heals and opens up. During this time, we will continue to monitor your pressure and keep you on your current medications until we see a stable improvement.
Some patients notice a drop in pressure within a few weeks, while others take longer. If your pressure does not decrease enough after several weeks, we may treat the other half of the drainage angle or consider additional therapies.
On average, responders achieve an eye pressure reduction of about 20 to 25 percent, but individual results vary and some patients do not respond.
Side Effects, Risks, and When to Call Us
Most side effects after ALT are mild and go away on their own within a few days. You may notice some redness, light sensitivity, or a gritty feeling in your eye. Blurred vision can occur right after the procedure but usually clears as any inflammation settles. These symptoms are part of the normal healing process.
- Mild redness or bloodshot appearance
- Sensitivity to bright lights
- Gritty or scratchy sensation
- Temporary blurring of vision
A small amount of blood in the front of the eye (microhyphema) can occur and usually clears on its own.
Although uncommon, more serious problems can occur. A sudden spike in eye pressure right after the procedure is the most important risk, which is why we check your pressure before you leave. Other possible complications include significant inflammation inside the eye, peripheral anterior synechiae, microhyphema, transient corneal edema, damage to surrounding structures, scarring of the drainage tissue, failure to lower pressure adequately, or a need for urgent additional treatment. In very rare cases, glaucoma can worsen.
These complications are unusual when the procedure is performed carefully and followed up properly, but it is important to be aware of them and attend all scheduled visits.
Call our office right away if you experience severe pain that does not improve with over-the-counter pain relievers, sudden vision loss, or intense redness and swelling. A sudden increase in floaters, flashes of light, or a curtain over part of your vision could signal a more serious problem. Do not wait for your scheduled follow-up if you have any of these symptoms.
- Severe or worsening eye pain
- Sudden decrease in vision
- Heavy discharge or thick crusting
- Flashes of light or new floaters
- Halos around lights with headache or nausea
- Symptoms that feel much worse instead of better
Some blurriness right after the procedure is normal, but any new or lasting vision changes should be reported to our team. If your vision does not return to its pre-procedure level within a few days, or if you notice new blind spots or distortions, contact us for an urgent evaluation. Quick assessment helps us identify and treat any complications early.
Keep our office number handy and do not hesitate to reach out with concerns. We would rather check on you and find everything is fine than have you wait too long with a problem.
Frequently Asked Questions
Both ALT and SLT lower eye pressure by treating the trabecular meshwork with laser energy, but SLT uses a different type of laser that causes less permanent damage to the tissue. Because SLT is gentler, it can often be repeated more easily if pressure rises again, and it has become the preferred laser option in 2025.
We may still consider ALT in specific cases based on equipment availability, cost, and your individual treatment history. Initial pressure-lowering can be similar between ALT and SLT, but SLT tends to have fewer side effects and is easier to repeat.
Many patients continue to use at least some glaucoma drops after ALT, though you may need fewer medications or lower doses if the laser works well. The goal is to reach and maintain your target eye pressure, and ALT is one tool that can help reduce your medication burden.
Our eye doctor will adjust your drop regimen based on your pressure readings over the weeks and months following the procedure.
ALT can sometimes be repeated, but because it causes small burns that create scar tissue, there is a limit to how many times we can safely treat the same area. If your pressure rises after an initial ALT, we may treat the other half of the drainage angle if it was not done before.
However, if both halves have been treated or if scarring is a concern, repeat ALT has lower success rates, and we will likely move to other options like SLT, different medications, or glaucoma surgery.
The procedure itself should not be painful because we use numbing drops to keep you comfortable. You may feel mild pressure from the contact lens or see bright flashes of light, but most patients tolerate it easily.
Afterward, some scratchiness, mild aching, or light sensitivity can occur, but over-the-counter pain relief and your prescribed anti-inflammatory drops usually manage any discomfort well.
The benefit of ALT varies from person to person. Some patients enjoy lower pressure for several years, while others see the effect fade after a year or two. On average, many people maintain some degree of pressure reduction for two to five years.
Regular follow-up visits allow us to track your pressure trends and adjust your treatment plan if the laser effect begins to wear off over time. Effectiveness often wanes over time, and repeat treatments usually have a smaller effect than the first.
Getting Help for Argon Laser Trabeculoplasty
If you have been diagnosed with glaucoma or high eye pressure and are interested in learning whether ALT or another laser treatment might be right for you, schedule an appointment with our eye doctor. We will review your medical history, perform a thorough examination, and discuss all your options to create a personalized plan that aims to protect your vision for the long term.