Glaucoma Treatment
Selective laser trabeculoplasty (SLT) is a gentle, 5 to 10 minute in-office laser that lowers eye pressure without daily drops. Large trials now support it as a first treatment for open-angle glaucoma. Here is how it works, what to expect, how to prepare and recover, and why it matters so much if you also have dry eye.
A Change in Practice
For decades, glaucoma treatment started with daily eye drops. The evidence now supports starting with SLT laser for most people with open-angle glaucoma or high eye pressure.
The turning point was the LiGHT trial, a large randomized study of 718 people with newly diagnosed open-angle glaucoma or ocular hypertension. Half started with SLT and half started with eye drops.
After three years, about three in four people who had SLT first needed no drops at all to keep their pressure at target. After six years, the SLT-first group had less glaucoma progression and needed fewer glaucoma and cataract operations. The authors concluded that SLT should be offered as a first-line treatment.
The UK's national guideline body, NICE, made SLT its recommended first treatment in 2022, and the American Academy of Ophthalmology's glaucoma guideline lists laser trabeculoplasty as an initial therapy.
An in-office laser that takes about 5 to 10 minutes
No cutting, no stitches, and no general anesthesia; numbing drops only
Lowers eye pressure by helping fluid drain out of the eye
Can replace daily drops for many people, or reduce how many you need
Can be repeated if the effect wears off over time
Have dry eye as well as glaucoma? Read why SLT matters even more for you.
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How It Works
Glaucoma damages the optic nerve, most often because fluid inside the eye does not drain well enough and pressure builds up. SLT works on the eye's own drain.
Selective
SLT uses very short pulses of laser light aimed at the drainage tissue, called the trabecular meshwork. The energy is absorbed by pigmented cells and leaves the surrounding tissue untouched.
Biological
The treated cells trigger the eye's own repair response, which helps clear and remodel the meshwork so fluid can drain more easily and pressure comes down.
Gentle
Older laser treatments burned the drain. SLT does not, which is why it is so well tolerated and why it can be safely repeated.
Flexible
Having SLT does not rule out drops, sustained-release implants, or glaucoma surgery later if they are ever needed.
SLT vs. Eye Drops
Drops work when they are used every day, exactly as prescribed, for life. SLT takes the daily routine out of the equation.
Freedom from drops
In the LiGHT trial, 74% of people treated with SLT first needed no drops at three years, and about 70% of eyes were still at target pressure without drops or surgery at six years.
Better control
Over six years, glaucoma progressed in 19.6% of eyes treated with SLT first, compared with 26.8% of eyes started on drops. Vision loss on field testing was also slower in the SLT-first group.
Fewer operations
Over six years, 13 eyes in the SLT-first group needed trabeculectomy surgery, compared with 32 in the drops-first group, and there were fewer cataract operations too.
Fewer side effects
No missed doses, no bottles to refill, no red or stinging eyes, and none of the body-wide side effects some drops can cause, such as slowed heart rate or breathing problems with timolol.
Is It Right for You?
SLT works best when the eye's drainage angle is open. A careful exam, including a look at the angle itself, tells us whether it is a good fit.
Newly diagnosed open-angle glaucoma
Ocular hypertension (high eye pressure) that needs treatment
People who have trouble using drops every day, or who forget doses
People with side effects, allergies, or stinging from drops
People with dry eye or ocular surface disease
Pseudoexfoliation and pigmentary glaucoma, which often respond well
Narrow or closed drainage angles (angle-closure glaucoma)
Glaucoma caused by inflammation inside the eye (uveitic glaucoma)
Neovascular glaucoma and some other secondary glaucomas
Very advanced glaucoma that needs a larger pressure drop than SLT alone can give
Even when SLT is not the right first step, it may still play a role alongside other treatments.
The Procedure
SLT is done in the office, sitting at a laser that looks much like the microscope used for your eye exams. Most people are surprised by how quick and comfortable it is.
Step 1
We check your eye pressure and place a drop that helps prevent a pressure spike after the laser, then a numbing drop.
Step 2
You rest your chin and forehead on the laser. A special lens with a soothing gel is placed gently on the eye to hold the lids open and focus the laser on the drain.
Step 3
You see brief flashes of light and may hear soft clicks. Most people feel nothing, or at most mild pressure. The treatment itself takes only a few minutes.
Step 4
The lens is removed, and we recheck your eye pressure after a short wait before you go home, to make sure it has not spiked.
Before and After
There is very little to do, but a few simple steps make the day smoother and the result easier to judge. Always follow the specific instructions we give you.
Keep using your glaucoma drops as usual unless we tell you otherwise.
Eat and take your regular medicines normally. No fasting is needed.
Bring a list of all your medicines, including eye drops.
Plan for someone to drive you if you can. Your vision may be blurry for a few hours from the gel and drops.
Skip eye makeup on the day of treatment.
Mild ache, redness, light sensitivity, or blur is common for a day or so. Over-the-counter pain relievers are usually enough.
Most people return to normal activities the same day or the next day.
Do not rub the treated eye on the day of the laser.
Use any drops we prescribe exactly as directed, and keep using your glaucoma drops until we tell you to stop.
If you have dry eye, keep using preservative-free artificial tears; they make the eye more comfortable as it settles.
The pressure-lowering effect builds gradually over several weeks. We recheck your pressure at follow-up visits to measure your response and decide whether any drops can be reduced or stopped. Contact an eye doctor's office the same day if you have severe pain, worsening vision, or increasing redness after the laser.
Glaucoma and Dry Eye
Dry eye and glaucoma often go together, and glaucoma drops are part of the reason. For these patients, reducing drops can protect both the eye surface and the optic nerve.
In one study of people with glaucoma, 59% had dry eye symptoms and 78% had unstable tears. Many glaucoma drops contain a preservative called benzalkonium chloride (BAK), and each additional BAK-preserved drop roughly doubled the odds of visible damage to the eye surface.
The result is a frustrating cycle: drops sting, so people skip doses, and skipped doses mean less control of glaucoma.
Fewer or no glaucoma drops means less preservative exposure, so the eye surface can recover.
A healthier surface means better comfort and clearer, steadier vision.
Glaucoma control no longer depends on using drops that hurt.
A healthy eye surface also gives more accurate measurements if you later need cataract surgery.
An Honest Look
SLT is one of the safest treatments in glaucoma care. In the six-year LiGHT results, there were no serious laser-related complications. It still has limits worth knowing.
A temporary rise in eye pressure soon after treatment, which is why we check it before you leave
Mild inflammation, ache, or redness for a few days
Blurry vision for a few hours
Rarely, prolonged inflammation or swelling of the cornea
It cannot restore vision that glaucoma has already taken.
It does not work for everyone; some eyes respond only a little.
The effect can fade over a few years, although it can usually be repeated.
Regular checkups are still essential, because glaucoma is lifelong.
What the Research Says
Evidence reviewed October 2026.
The Lancet, 2019
In 718 people, 74.2% of those treated with SLT first needed no drops at three years, and none needed glaucoma surgery, compared with 11 in the drops group.
Read the study ↗Ophthalmology, 2023
SLT first gave better long-term control than drops, with less progression, fewer trabeculectomies and cataract surgeries, and no serious laser-related adverse events.
Read the study ↗Ophthalmology, 2026
Visual field loss was slower over six years in eyes treated with SLT first, and the authors recommend SLT as the preferred first treatment.
Read the study ↗Journal of Glaucoma, 2008
59% of glaucoma patients had dry eye symptoms, and each additional BAK-preserved drop roughly doubled the odds of eye surface damage.
Read the study ↗FAQ
Fellowship-trained glaucoma specialist Dr. Eslani can tell you whether laser, drops, or another option is the best first step for your eyes.