Selective Laser Trabeculoplasty (SLT)

What is SLT?

This laser is used to treat glaucoma by lowering eye pressure. The balance of fluid produced and drained inside the eye creates your eye pressure. The drain of the eye is the trabecular meshwork. When the drain doesn’t work well, the fluid that circulates in the eye can’t leave fast enough and the eye pressure rises. This laser procedure lowers eye pressure by increasing the drainage of fluid out of the eye through the trabecular meshwork.

How effective is SLT?

Generally 8 out of 10 people will have lower eye pressure after this laser procedure. The pressure drop is expected to be around 10-20%. The effectiveness of this laser treatment will depend somewhat on the pigment content of the trabecular meshwork. The effect of the laser is not permanent, wearing off within a few years. Depending on your response, the laser may be repeated more than once. If you are taking eye drops for glaucoma, you will most likely still need them after this laser treatment.

Will the laser help my vision?

No. The goal is to lower the risk of future vision loss by lowering eye pressure.

What can I expect during the procedure? Does it hurt?

The laser procedure is performed in a surgery center. You will be there for perhaps one and a half hours, but the procedure takes just several minutes. The procedure is performed while sitting at a slit lamp, like when having an eye exam. A temporary contact lens will be placed for a few minutes to help focus the laser light. Numbing drops will be used. Patients only rarely describe discomfort. When the contact lens is removed, vision can be blurry for about an hour because of an ointment used on the contact lens. You may be placed on eye drops for about a week to prevent inflammation. Sometimes, the laser needs to be repeated if the first treatment did not lower eye pressure.

What are the risks of SLT?

This laser procedure is overall very safe. Serious risks are very rare but could include vision loss. Mild inflammation is possible that would resolve with eye drops over several days to weeks. A transient increase in eye pressure may occur that would require extra eye drops. The contact lens used on occasion may scratch the eye, which would be expected to heal within several days.