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PubMed This is a summary of 20 peer-reviewed journal articles Updated
Ophthalmology

Standard Treatment: Drops & Laser (SLT)

At a Glance

For open-angle glaucoma, both eye drops and selective laser trabeculoplasty (SLT) lower eye pressure to a personalized target that helps protect the optic nerve. The best first option depends on eye findings, health conditions, side effects, cost, and follow-up needs.

Lowering the pressure inside your eye—known as intraocular pressure (IOP)—is the most established treatment proven to slow the rate or reduce the risk of progression in open-angle glaucoma [1]. This remains true even if your pressure is already in the statistical “normal” range; for those with normal-tension glaucoma, further reducing the pressure still helps protect the optic nerve [2].

The Concept of Target IOP

There is no single “correct” eye pressure that works for everyone. Instead, your doctor will determine a target IOP. This is an individualized goal range designed to be low enough to prevent further damage to your unique optic nerve [3].

To set this target, your doctor considers several factors:

  • How high your pressure was when you were diagnosed.
  • How much damage is already visible on your scans and visual field tests.
  • Your age, life expectancy, and overall health.
  • The thickness of your cornea [4].

Your target is not set in stone; if your doctor sees signs of progression during your checkups, they will likely lower your target further [5].

First-Line Option 1: Eye Drops

For many years, daily eye drops have been the standard first treatment. There are several classes of medications, each with different mechanisms and potential side effects:

  • Prostaglandin Analogs (e.g., latanoprost, travoprost): Often used once a day in the evening, these help fluid drain out of the eye [6]. They are highly effective but can cause eye redness, eyelash growth, darkening of the iris or eyelid skin, and a hollowing effect around the eye [7][8].
  • Beta Blockers (e.g., timolol): These reduce the production of eye fluid. Because they can be absorbed into the bloodstream, they can cause systemic side effects like a slowed heart rate, low blood pressure, fatigue, or bronchospasm. You must tell your doctor if you have asthma, COPD, or heart rhythm issues.
  • Alpha-Agonists (e.g., brimonidine): These both reduce fluid production and increase drainage. They can sometimes cause allergic reactions in the eye or fatigue.
  • Carbonic Anhydrase Inhibitors (e.g., dorzolamide): These reduce fluid production.
  • Rho-Kinase Inhibitors (e.g., netarsudil): A newer class that targets the trabecular meshwork directly to improve drainage.

Managing Drop Side Effects

Many drops contain a preservative called benzalkonium chloride (BAK), which can cause or worsen dry eye, burning, and inflammation [9]. If you find the drops uncomfortable, ask your doctor about preservative-free versions, though they are not available for every medication and may be more expensive [10][11]. Do not stop or change your eye drop regimen without contacting your prescribing doctor first.

First-Line Option 2: Laser Treatment (SLT)

Selective Laser Trabeculoplasty (SLT) is an in-office procedure that uses a laser to stimulate the eye’s natural drainage tissue to work more efficiently [12]. Depending on your diagnosis, angle visibility, and local guidelines, SLT is increasingly recommended as a primary first-line treatment option alongside or instead of drops [13][14].

  • How it works: The laser targets specific pigmented cells in the drainage area without causing structural damage [15].
  • Effectiveness: In a major clinical trial of select newly diagnosed patients (the LiGHT trial), about 74% of participants who received SLT were able to remain at their target pressure without daily drops three years later [14].
  • Duration and Reality: SLT is rarely a permanent fix. The effect often wears off over time, meaning you may still need drops eventually, or the laser may need to be repeated [16][17]. It does not eliminate the need for regular monitoring.
  • Risks: SLT is generally safe, but side effects can include temporary inflammation, discomfort, or a brief, manageable spike in eye pressure immediately after the procedure [18][19].

Choosing the Right Path for You

The choice between drops and laser should be a shared decision with your doctor. Before you choose, consider your ability to pay for and instill drops daily, your existing dry eye symptoms, any systemic health conditions (like asthma or pregnancy), and your willingness to attend follow-up visits. Regardless of the path you choose, consistent follow-up is required to protect your vision [20].

Common questions in this guide

What does a target IOP mean in open-angle glaucoma?
Target IOP is the eye-pressure range your doctor chooses to reduce the chance of further optic nerve damage. It is based on your pressure at diagnosis, existing damage on scans and visual-field tests, age, life expectancy, overall health, and corneal thickness. If testing shows progression, the target may be lowered.
Should I start open-angle glaucoma treatment with eye drops or SLT?
Both daily eye drops and SLT can be first-line treatments for open-angle glaucoma. The choice depends on your diagnosis, the visibility of the drainage angle, local guidelines, dry-eye symptoms, other health conditions, cost, ability to use drops, and willingness to attend follow-up visits. Discuss the options as a shared decision with your eye doctor.
Can glaucoma treatment help if my eye pressure is in the normal range?
Yes. In normal-tension glaucoma, eye pressure may be within the statistical normal range, but lowering it further can still help slow progression or reduce the risk of additional optic nerve damage. Your doctor will set an individualized pressure target based on your eye findings and test results.
How does SLT lower eye pressure, and does it last permanently?
SLT is an in-office laser procedure that targets selected pigmented cells in the eye’s drainage area, stimulating the tissue to move fluid more efficiently without intentionally causing structural damage. Its pressure-lowering effect often wears off over time, so some people later need eye drops or repeat SLT. Regular monitoring remains necessary.
How effective is SLT for newly diagnosed glaucoma?
In the LiGHT trial, about 74% of selected newly diagnosed participants who received SLT stayed at their target pressure without daily drops three years later. This result does not guarantee the same outcome for every patient, because the response varies with individual eye findings and circumstances.
What side effects can open-angle glaucoma eye drops cause?
Glaucoma drops can cause different side effects depending on the medicine. Prostaglandin analogs may cause redness, eyelash growth, or darkening of the iris or eyelid skin; beta blockers may slow the heart rate, lower blood pressure, cause fatigue, or cause breathing problems. Tell your doctor about asthma, COPD, or heart-rhythm problems before using a beta-blocker drop.
What should I do if my glaucoma drops burn or worsen dry eye?
Many glaucoma drops contain benzalkonium chloride, a preservative that can worsen dry eye, burning, or inflammation. Ask whether a preservative-free version is suitable if drops irritate your eyes, although it may not be available for every medicine and can cost more. Do not stop or change your drops without first contacting the prescribing doctor.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What is the specific 'target IOP' you have set for my eyes, and how did you decide on that number?
  2. 2.Based on my lifestyle, eye health, and other medical conditions, would you recommend starting with laser treatment (SLT) or daily eye drops?
  3. 3.If we choose drops, can we start with a preservative-free version to protect the surface of my eyes?
  4. 4.What is the success rate of SLT in your experience, and how long does the pressure-lowering effect typically last?
  5. 5.What side effects should I watch for with my prescribed drops, and which ones would require me to stop using them?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (20)
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This page is for informational purposes only and does not constitute medical advice. Your eye doctor should set your target IOP and guide decisions about drops, SLT, and any medication changes.

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