Selective Laser Trabeculoplasty...What do you need to know as a patient?
Selective Laser Trabeculoplasty, SLT, is a laser procedure that is used to lower intraocular pressure, IOP, in patients with glaucoma. It can be used as an initial treatment for glaucoma or in conjunction with medication eye drops.
With SLT, the laser energy is applied to the drainage tissue in the eye, the trabecular meshwork. A biological change is induced in this tissue that allows better drainage of fluid through the tissue and out of the eye. The increased drainage results in a lowering of IOP. It may take 1-3 months to obtain the maximum result.
Why is it called Selective? This is due to the unique property of this type of laser, in that it is only taken up by selected pigmented tissue in the eye. This results in minimal heat energy absorption.
Studies have demonstrated that SLT can lower IOP by about 30% when used as an initial treatment. This is similar to the most commonly used class of medication eye drops, prostaglandins. Typically, the result will last for 1-5 years. The fact that SLT is a “cold laser” allows it to be repeated in patients who observed success with treatment, but now experience a fading of the effect after a few years.
Some patients will reach a sufficient lowering of IOP with SLT alone. Others will require the use of medication eye drops as well. This is similar to patients who are being treated solely with medications, where around 50% require more than one medication. You can think of SLT as being equivalent to one medication. SLT is not a cure for glaucoma. Just like patients on medications or who have had other surgeries, appropriate follow up and testing with one’s eye doctor is important.
SLT is successful at lowering IOP in around 80% of patients. If SLT does not work for a patient, the glaucoma then needs to be treated by other means such as medications or surgery. The laser does not affect the success rates of these other treatment options.
A main advantage of SLT is its favorable side effect profile. Post-operative inflammation is common, but generally mild. It is often simply treated by doctor observation. Occasionally, eye drops are used. About 5% of the time there is a temporary 24-hour spike in IOP following the procedure. This is typically managed by the temporary use of glaucoma medications.