Selective Laser Trabeculoplasty (SLT)

What is Selective Laser Trabeculoplasty (SLT)?

This is a laser procedure to treat glaucoma. Your physician will let you know if this laser is a suitable option for you. Generally speaking, it is offered to people with open angle glaucoma who have high eye pressure despite being on topical eye drops, or those who might be intolerant of further medications. Usually, this laser procedure can help lower your eye pressures in conjunction with using your regular eye drops. The effect of this laser is only temporary, and lasts anywhere from 6 months to 5 years (determined by regular monitoring of the eye pressures). It can be repeated up to 4 times per eye.

How does SLT work?

Essentially, this laser works to improve outflow in the drainage canals inside your eyes so that fluid drains out of the eyes more efficiently. This leads to lower pressure overall. The laser treatment may take about 6-8 weeks to reach peak effect. Initially, there may be a rise in the pressure with the temporary inflammation that happens after laser. This can usually be treated using extra medications in the form of pills or extra topical drops as prescribed by your doctor.

What should I expect on the day of the laser procedure? Is it painful?

This procedure takes a few minutes per eye. You need to have some preparatory drops to make sure your eye pressure does not increase from the temporary inflammation caused by the laser.

After the technician takes some initial measurements and applies the preparatory drops to your eyes, you will wait for a few minutes while the drops work. You will then be called into the laser room for the laser procedure, which will be performed by your Ophthalmologist. The actual treatment will take about 5 minutes or so. A lens with a layer of lubricating gel will be placed on your eye to hold your eyelids back and direct the laser. This will feel strange but does not cause pain. You may feel the lens moving slightly as the doctor directs the laser. Some people feel a slight pain or prickly feeling when the laser is applied. This lasts a few seconds at most. It is common to get some inflammation after the laser, and to experience slightly blurry vision after the procedure. This should clear up within a few minutes to hours. Occasionally some people may feel light-headed and faint, especially those who are quite anxious about the laser. If this happens, we may have to postpone the procedure and allow you to recuperate by lying down in an adjacent room. Fainting with laser procedures is not that common, but happens to some people.

After the laser, our assistants at the front reception will give you a prescription for Nevanac ® (or equivalent substitute non-steroidal anti-inflammatory) eye drops to be used 3 times per day for 4 days in the lasered eye(s). This is a non-steroidal anti-inflammatory drop that decreases the inflammation after the laser procedure. You should discard the bottle after completing the 4-day course.

Our assistants will tell you when your eye pressure will be taken, approximately one hour after the laser. It is important to check that your eye pressure is at an acceptable level prior to discharging you for the day. You do not have to wait in the office for an hour. Many people choose to have a coffee downstairs in the mall, or do some other errands, and then return in an hour.

Occasionally, your eye pressure may be higher after the laser procedure. It may be necessary to give you some extra eye drops or oral medications temporarily to lower the pressure. Your doctor may wish to check you again the next day if the pressure is very high after laser, which is not common but can happen. Rarely, if the pressure elevation is not controlled by medication alone, surgery may have to be considered to lower it. This is a rare circumstance that can happen especially in people with severe glaucoma.

What symptoms should I expect after SLT laser?

After SLT laser, you will likely not notice anything different. The pressure will be monitored and should be in normal range after 6-8 weeks. If your pressure becomes higher instead of lower, you may experience discomfort, pain and blurred vision and should call your doctor's office, or go the Urgent Care at Misericordia Health Centre (or locally).

When should I be checked after the laser?

After the laser, you will have to get your pressure checked at one week and one month post-laser, either by your own Optometrist or at GEM Clinic (if you do not have an Optometrist). You will still need to be monitored for glaucoma after the laser, either by your own Optometrist or Ophthalmologist.

Will I still need to use eye drops after the laser?

If you used eye drops before the laser, you need to continue using them after the laser. These drops in addition to the laser effect should bring your eye pressure down to normal range and prevent further damage to your optic (eye) nerves and in turn prevent (further) vision loss.