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Glaucoma care aims to protect the vision a person still has. Lowering pressure inside the eye can slow damage to the optic nerve, but treatment cannot restore nerve tissue already lost. Two developments have broadened the choices: using selective laser trabeculoplasty earlier, and offering selected patients smaller-incision operations called minimally invasive glaucoma surgery, or MIGS.
These treatments solve different problems. The right choice depends on the type of glaucoma, the pressure needed to protect the nerve, the amount of existing damage and whether cataract surgery is also planned.
How SLT helps fluid leave the eye
Selective laser trabeculoplasty, usually shortened to SLT, applies brief laser pulses to the trabecular meshwork, part of the eye’s natural drainage pathway. Its biological effects can improve fluid outflow and lower pressure. The treatment is performed through a viewing lens placed on the numbed eye; it does not involve an incision into the eye.
SLT is an established option for appropriate open-angle glaucoma and ocular hypertension. In its 2022 guidance, the UK’s NICE recommends offering 360-degree SLT as an initial treatment for eligible people with newly diagnosed, non-advanced chronic open-angle glaucoma, excluding cases associated with pigment dispersion syndrome. Eligibility is assessed by an eye specialist; this recommendation does not apply to every form of glaucoma. NICE recommendations
What the longer-term research found
The LiGHT randomized trial compared a laser-first pathway with an eye-drop-first pathway in previously untreated patients with open-angle glaucoma or ocular hypertension. At six years, 69.8% of eyes in the laser-first group were at or below their target pressure without medication or incisional surgery. Repeat SLT was allowed within the treatment pathway, so this figure should not be read as the result of one laser session lasting six years for everyone.
Disease progression was also less frequent in the laser-first group. The trial supports discussing SLT early in suitable cases, while leaving room for eye drops and other procedures when needed. Its results are group averages from a monitored clinical trial, not a personal prediction. LiGHT six-year results, 2023
Where MIGS fits
MIGS describes several operations, rather than a single device. Some open or bypass part of the drainage pathway; others improve fluid movement through it. Many procedures are considered for mild-to-moderate open-angle glaucoma, sometimes during cataract surgery, with the aim of lowering pressure or reducing reliance on drops.
In the HORIZON randomized trial, adding a particular Schlemm’s canal microstent to cataract surgery reduced medication use and increased the chance of achieving pressure control with fewer or no drops compared with cataract surgery alone over five years. Those findings apply to the studied device and patient group. They do not establish that every MIGS procedure works equally well or that an implant is suitable for every eye. HORIZON five-year report, 2022
Benefits have to be weighed against limits
SLT can cause temporary discomfort, redness, light sensitivity or blurred vision. Pressure can rise after treatment, which is one reason follow-up checks matter. Its effect can diminish, and some patients still need drops or further laser treatment. NICE evidence discussion
MIGS involves surgery and carries procedure-specific risks, including bleeding, inflammation, pressure changes and possible need for further treatment. An eye with advanced damage may need a lower pressure than a drainage-angle procedure can reliably achieve. Trabeculectomy or a drainage implant may therefore be more appropriate in some cases. A smaller operation is not automatically the most effective choice for the pressure target. National Eye Institute: glaucoma surgery
Questions worth bringing to your appointment
Ask: What is my target pressure? Is the drainage angle open? Is my glaucoma stable on visual-field and optic-nerve tests? What reduction in drops is realistic? What happens if the procedure does not achieve the target?
A comprehensive eye examination provides a starting point for that discussion. Continue prescribed drops until your treating clinician changes the plan. Even successful treatment requires ongoing pressure measurements and monitoring of the nerve and visual field.
Related reading
This article provides general education and cannot determine which treatment is right for an individual. Diagnosis and treatment require an ophthalmologist’s assessment. Technologies, approvals and availability vary by country and centre.
Sources
- Gazzard G et al. Laser in Glaucoma and Ocular Hypertension (LiGHT) Trial: Six-Year Results of Primary Selective Laser Trabeculoplasty versus Eye Drops for the Treatment of Glaucoma and Ocular Hypertension. Ophthalmology 130:139–151. (2023-02; online 2022-09-17).
- NICE NG81. Glaucoma: diagnosis and management. Recommendations. (Updated 2022-01-26).
- NICE NG81. Rationale and impact. (Updated 2022-01-26).
- Ahmed IIK et al. Long-term Outcomes from the HORIZON Randomized Trial for a Schlemm’s Canal Microstent in Combination Cataract and Glaucoma Surgery. Ophthalmology 129:742–751. (2022; erratum 2024).
- National Eye Institute. Glaucoma Surgery. (Updated 2026-08-20).
Evidence checked: 5 October 2026.
