What is Selective Laser Trabeculoplasty (SLT)?

SLT is a type of laser procedure that treats open angle glaucoma. Fluid (know as aqueous humour) is continuously formed in the eye and drained away from the eye. We need this fluid for our eye health. If the fluid cannot drain normally the pressure will build up in the eye and this can damage the optic nerve. This type of optic nerve damage is known as glaucoma.  In SLT a laser is applied to the area through which fluid drains (trabecular meshwork). The laser modulates the biochemistry of the trabecular meshwork and facilitates fluid outflow. The procedure does not work instantly. It can take several months to know if this procedure is successful. This procedure takes only a few minutes but you will be in the office for 1 ½ to 2 hours as you require drops prior to the procedure and need to have your pressure checked forty five minutes after the procedure is done.

How is this procedure done?

  • You will be given numbing eye drops.

  • You will be positioned comfortably at the laser. The laser is attached to the examination microscope your doctor uses to examine your eyes at each visit. The laser itself makes some noise and flashes a low level light.

  • The doctor will put a lens on the surface of your eye. You are able to blink gently.

  • The doctor will tell you in which direction to look during the procedure.

  • Between 50 and 100 shots are fired during this procedure. It is possible you may feel mild discomfort with some of these shots.

  • Following the procedure, you will receive more pressure lowering drops and anti-inflammatory drops.

  • You will be asked to wait 45 minutes after your procedure for a pressure check. You will receive a prescription for your post op drops at this time and if you wish, you can use the time to purchase your drops at the pharmacy.

What are the risks of SLT?

  1. Failure to lower eye pressure :  If this surgery does not lower your eye pressure at all or enough, it can be repeated.

  2. Sudden increase in eye pressure:  Alphagan eye drops are used before the procedure to prevent a pressure rise. If your pressure does rise you will be sent home with pressure lowering eye drops or pills to be used for a few days. Rarely,  surgery done in an operating room is required to lower the pressure.

  3. Inflammation:  You will be given a prescription for mild anti-inflammatory steroid eye drops. If you do not develop redness, pain or light sensitivity after the procedure, there is no need to fill out the prescription.

  4. Headache: sometimes the pre op drops can cause headaches. If you have a headache please ask one of our administrative staff at the front desk for Tylenol.
    Blurred vision: Your vision may be blurred for several hours after the procedure











  • Does the laser hurt? 
    You may feel mild discomfort with some of the laser shots. Pain is very unusual.


  • How long will I be in the office?
    On average you will be in the office for 90 minutes to 2 hours. Your pre-op eye drops must take effect and your pressure needs to be checked 45 minutes after your procedure.

  • Can I drive to the procedure?
    It is best not to drive yourself to this procedure.

  • I am very nervous. Is it possible for me take something to help me stay calm during this procedure?
    If you are extremely anxious, we can give you a prescription for Ativan to use prior to the procedure.

  • Do I need any medicine after this? 
    You will receive a prescription for anti-inflammatory medication.  If your eye is red, painful or light sensitive, please fill out the prescription. If not, do not use any drops. We do not encourage routine use of post op drops as it is thought that mild inflammation contributes to the success of this procedure

  • What kind of follow up do I need?
    You will be seen 6 to 12 weeks following the procedure at our office. Before leaving the office on the day of the surgery, book a follow up appointment to see Dr. Goldberg/ Dr. Hinton. 

  • Can I stop my glaucoma eye drops?
    If you are on glaucoma drops, you must continue using your eyedrops as directed. In some cases, you will be asked to stop an eye drop 1 week prior to your 3 month follow up examination. This helps the doctor know if it is possible to take you off of one of your glaucoma medications.

  • Can I have both eyes lasered on the same appointment?
    In general, if both eyes require this procedure, they are done together on the same appointment.

  • How effective is SLT?
    SLT lowers the eye pressure by about 30% when used as initial treatment. This effect may be reduced if you are already using one or more glaucoma medications

  • How long does the effect last?
    The effect will generally last between 1-3 years, and sometimes longer than that. If it does not last at least 6-12 months, it is usually not considered successful.

  • What happens if it wears off?
    If SLT is effective at lowering eye pressure but this wears off over several years, the procedure can be repeated, but the second treatment may not be as effective as the first and may not last as long. Alternatively, you may choose to add a glaucoma eye drop medication.

  • What happens if it doesn’t work?
    If SLT fails to work, your glaucoma will be treated by other means such as medications or surgery done in the operating room. The laser does not affect the success of these other types of treatment.

  • Is this procedure covered by OHIP?
    Yes, SLT is covered by OHIP.