SLT Laser

What is SLT?

Selective laser trabeculoplasty (SLT) is a non-invasive treatment to reduce intraocular pressure in open-angle glaucoma or ocular hypertension, when the angle is open and the clinical picture allows it. Compared with older trabeculoplasty techniques, SLT uses low energy and selective action, limiting thermal damage and allowing repetition in selected cases.

It is part of the glaucoma treatment plan alongside drops and surgical treatment, as an alternative or complementary option. In many international guidelines, SLT is compared with starting or adding an eye drop as a first-line option in selected open-angle glaucomas, always after a full clinical assessment and never as a substitute for monitoring.

It does not replace regular monitoring of the optic nerve and vision: visual fields and RNFL analysis (OCT) remain central, together with pressure measurements and gonioscopy where indicated.

How does it work?

SLT selectively targets pigmented cells in the drainage angle with low-energy laser pulses; the action is limited to cells containing melanin, without extensive damage to neighbouring tissue, unlike older, more destructive techniques.

The biological response (involving inflammatory cellular mechanisms) improves drainage of the aqueous humour and lowers pressure. The effect often peaks over the following weeks, and its duration varies individually. It does not cause the permanent structural changes of older methods, so repetition is possible only after clinical assessment.

Which patients is it suitable for?

SLT lowers pressure and its fluctuations, an important factor in glaucoma. In selected patients, the response can be equivalent to an extra eye drop, without the side effects of using multiple medications. It may be indicated when:

• There is difficulty adhering to eye drop use
• Side effects or allergic reactions are observed
• Medication is not enough to control pressure
• Further pressure reduction is needed without adding more medication

The decision is individualised (type of glaucoma, age, angle, nerve damage, coexisting conditions). In pseudoexfoliation or pigmentary glaucoma, SLT is often discussed earlier, always after a full examination.

Response is not the same for everyone; assessment is made with measurements over time and visual fields / OCT RNFL, not with a single "good" pressure reading. After the application, follow-up checks and gradual adjustment of eye drops follow under medical guidance. Temporary inflammation or a rise in pressure in the first days is rare but possible; instructions after the session are individualised.

The procedure

Gonioscopy confirms an open, suitable angle. SLT is performed at the practice under local anaesthesia. The application takes only a few minutes per eye.

Results, repetition and limitations

Response to SLT varies: many patients achieve satisfactory pressure reduction for months to years, while in others the benefit may be partial or shorter-lived. The clinical decision is based on the combination with eye drops, quality of life, adherence, and the side-effect profile. Repeat SLT is discussed selectively, after reassessing the angle and drainage, and with the aim of avoiding excessive medication burden.

SLT is not indicated when the angle is not adequately open; in a narrow or closed angle the discussion involves other options, such as YAG laser iridotomy, within the management of glaucoma. In the long term, monitoring with visual fields and OCT RNFL and pressure measurements remains central, regardless of laser treatment. For an overview of care options see services; for appointments, contact.

Individualisation of the plan (drop dosage, need for repeat laser or surgical treatment) is reviewed regularly, so that pressure, the optic nerve and vision are systematically monitored within the glaucoma plan.

Working with your ophthalmologist toward realistic pressure targets and recognising changes in vision supports the long-term stability of treatment.

Further information and appointments

For SLT, glaucoma or other options, see services or contact us for an appointment.