What is Selective Laser Trabeculoplasty (SLT)?
Selective laser trabeculoplasty, or SLT, is a laser procedure intended to treat open angle glaucoma. During SLT, a gentle laser is aimed at the drainage system of the eye (‘trabecular meshwork’) and is pulsed to stimulate it to open further, which helps to reduce the intraocular pressure (IOP). By lowering the IOP, SLT helps to prevent further damage to the optic nerve and preserve your vision. SLT is not designed or intended to help improve your vision.
How is the procedure performed?
The SLT procedure is performed in the clinic. The patient is seated in a chair and a few eye drops – including numbing drops – are instilled in the eye. The patient’s face is brought into the machine, and a specialized lens is placed onto the surface of the eye in order to visualize the drainage system. The laser is activated and the ophthalmologist will fire approximately 100 shots of low-energy laser into the drainage system to stimulate it. This takes roughly 10 minutes to perform. There is typically no pain involved with the laser, but patients may feel some pressure sensation during the procedure. After the procedure is completed, the lens is removed and the eye is washed, and additional drops are instilled. The patient then waits in the clinic for 30 minutes, after which the eye pressure is measured to ensure it is at an acceptable level. The patient can then leave, and typically returns 4-6 weeks later to assess the result.
Why has my ophthalmologist recommended this procedure?
Typically, SLT is recommended when the eye’s intraocular pressure (IOP) is felt to be too high and the eye is at risk from losing vision from glaucoma damage. This may be based on your ophthalmologist’s clinical judgment or on testing performed in the clinic. It can be used as a first-line treatment in patients diagnosed with glaucoma or as an adjuvant treatment (as a supplement to eye drops) to help reduce the eye pressure.
Are there any risks to the procedure?
In general, SLT is considered a safe and efficacious procedure with a very low complication rate. There are 3 general risks of SLT:
- Risk of inflammation – After the procedure, some inflammation can develop within the eye. This can cause eye redness and irritation for a few days following the procedure. Generally, this irritation is very mild and resolves within 5 days without treatment. Sometimes, it can cause noticeable discomfort, in which case an eye drops (topical NSAID) can be prescribed to help alleviate the symptoms. Rarely (less than 1% of cases) can develop significant inflammation which lead to corneal scarring and permanent blurred vision
- Risk of an eye pressure spike – In some patients, SLT causes a transient elevation in the IOP immediately after the procedure; this typically resolves within 1-2 days. This occurs on the order of 5% of cases. Typically, pressure-reducing drops are instilled before and after the procedure to reduce this risk, and patients have their eye pressure checked after the procedure to catch any spike.
- Risk of non-response – While SLT is felt to be very effective, some patients may not have an adequate reduction in their eye pressure. Many studies show success rates in around 70% of patients. Even if a reduction in the pressure is not seen at the follow-up visit, SLT is still felt to help in reducing fluctuations in eye pressure throughout the day. If it is felt that your eye pressure still needs further reduction, eye drops or other treatments can still be implemented – performing SLT does not limit future treatment options.
Are there alternatives to SLT?
While SLT is felt to be an effective and safe treatment, some patients may opt to use eye drops instead of laser treatment. In patients who are already using eye drops, this may mean adding an additional eye drop to your regimen.
In patients whose glaucoma is progressing despite maximal drop therapy, SLT may be the last treatment option before going on to surgery.
Does the laser effect last forever?
SLT’s effectiveness can vary widely from patient to patient. In some patients, the effect can last up to 5-6 years; in others, shorter than 6 months (if any effect at all). If a patient had a good result from SLT and the effect begins to wear off, it can be repeated.
Conclusion
In general, SLT is considered to be a safe, effective treatment for open angle glaucoma and can help to control one’s glaucoma without the use of daily eye drops. Please talk to your doctor if you have any other questions regarding the procedure.