What is Selective Laser Trabeculoplasty (SLT)?

SLT is one of the treatments for glaucoma.

Glaucoma is the name of a group of conditions in which the optic nerve at the back of the eye is damaged. This can cause you to lose your peripheral vision (side vision), and eventually the central vision as well.

Damage usually occurs from increased pressure in the eye.SLT is a simple procedure which can help to reduce to pressure in your eye.

How does SLT work?

In healthy eyes, fluid is able to drain through a series of channels called the trabecular meshwork. However in some people, these drainage channels do not work properly, and can cause the pressure in the eye to increase.

SLT uses short pulses of laser to unclog these drainage channels. It only targets cells containing a natural pigment called melanin.

In response, the body’s natural healing mechanisms go to work to rebuild these cells. This rebuilding process improves drainage and lowers the pressure in the eye. The surrounding, non-pigmented cells – as well as the rest of the eye – are untouched and undamaged.

How successful is SLT?

SLT is successful in about 50-70% of patients. When SLT is successful it can help reduce the number of drops you use to manage your glaucoma.

The benefits of treatment may wear off in time. It is thought that about half of all treatments stop working after five years, but SLT can be repeated.

It should be noted SLT is used to save the vision you have. It will not improve your vision or restore any vision you have lost.

What to expect on the day

Take your glaucoma drops as normal on the day of your treatment. SLT is carried out in the clinic and takes about 5-10 minutes per eye.

Before the procedure

  • First we will check the pressure of your eye
  • We will then put some anaesthetic drops in your eye to numb the eye. (This will only take a few minutes to work)

During the procedure

  • You will be seated in front of the laser machine which looks similar to the microscope used to examine your eyes in clinic.
  • A special contact lens is then placed on the surface of the eye. This is not painful but may feel strange
  • During the treatment you may hear clicking noises and see flashing lights
  • Most patients tolerate this treatment well but a few may feel some slight discomfort.

After the procedure

  • Your eye pressure will be measured about one hour after the procedure
  • Your vision will be blurred immediately following the procedure for a short period, so you cannot drive home afterwards
  • You will then have a post-operative appointment a few weeks later
  • It can take a few months for SLT to have its full effect on the eye pressure
  • If you were using anti-glaucoma eye drops before SLT, you should continue using them unless your doctor says otherwise

Some patients may be given an anti-inflammatory drops for one week following treatment

Side effects

SLT is a safe procedure and the risk of adverse effects is minimal but you need to be aware of the following information:

  • You may experience some redness, eye discomfort or blurry vision after the procedure for a short time – a few hours or sometimes a few days. This will gradually resolve on its own
  • Occasionally the pressure in the eye may increase immediately after the treatment and you may require extra eye drops following your treatment for a short time
  • Rarely the pressure in the eye can become very high and does not come down with medication so surgery may be required to lower the pressure
  • In very rare cases minor bleeding has been reported. However, this often settles down within a few days, CMO (swelling of retina) has been reported in rare cases.

What do I do if I get any of the above side effects?

As mentioned, redness, eye discomfort and blurriness tends to resolve over a few days.

However, if the pain in your eye gets worse, or if you lose vision, you can ring eye clinic for advice, or attend urgent care out of hours.

Fairhurst building eye clinic details:

Telephone number - 01282 804201

Opening hours

Monday to Friday 8am-8pm
Saturday 9am – 2pm
Sunday 9am – 2pm