SLT Laser

SLT stands for “Selective Laser Trabeculoplasty”. This is a treatment for glaucoma that is increasingly used around the world.


Glaucoma or raised eye pressure occurs when there is an imbalance of fluid produced by the eye and drainage out of the eye. Eye fluid “the aqueous” passes through some tiny filters called the “trabecular meshwork”. In glaucoma, these filters become clogged similar to a pool filter becoming clogged with leaves. The laser works by unclogging these filters, improving drainage and thus reducing eye pressure.

Unlike older forms of glaucoma laser treatment, numerous studies have shown SLT to be gentle, effective, and safe and can be repeated. Its effect on average lasts about 2-3 years although some patients have had benefit for more than 5 years.


This is performed as an outpatient procedure.

  1. 15 minutes before treatment, you will be given some drops to constrict your pupil and to reduce chances of a pressure rise. You will also be given some fluid tablets (please inform us if you have a Sulphur allergy).
  2. A contact lens is applied to your eye. This keeps the lids apart, steadies the eye and allows treatment with the laser. There is very little discomfort and the procedure takes about 5 minutes.
  3. You will be given anti-inflammatory drops to use for a week after the laser.

Follow up:

You will be seen 2 weeks later followed by another appointment in 6 weeks. An effect on pressure is often present by 2 weeks and by 6 weeks, the final effect is often present.


  1. It can be used as additional treatment for glaucoma patients whose pressure are inadequately controlled by drops.
  2. Nontolerance or Noncompliance with Glaucoma drops
    Some patients develop side effects to drops and laser can help to achieve control. It can also be used in patients who are non-compliant.
  3. Alternative to Drops.
    Increasingly the laser is being used as an alternative to drops to achieve pressure control.


Patients with Glaucoma are not cured of their problem with SLT laser. There is a tendency to think that patients do not have a problem as they are not instilling drops. The effect of SLT laser does wear off over time and hence it is important to have continued follow up to monitor for pressure rise. Often the laser treatment can be repeated or alternatively drops will be prescribed.