What is selective laser trabeculoplasty?

Selective laser trabeculoplasty (SLT) is a procedure used to treat patients with glaucoma, by reducing pressure on the eye. It can also be used to reduce the risk of patients with raised eye pressure developing glaucoma.

Glaucoma is usually caused by fluid building up in the front part of the eye, which increases pressure inside the eye. SLT uses a laser beam to improve fluid draining out of the eye, thereby lowering pressure.

What causes increased pressure on the eye?

Raised pressure in the eye occurs when the trabecular meshwork, a ring of tissue responsible for the drainage of fluid inside the eye (aqueous humour), starts to fail.

High eye pressure can cause damage to the optic nerve and, over time, this can cause loss of vision. Glaucoma is the term given to optic nerve damage caused through this process.

What happens before the procedure?

  • Your vision and intraocular pressure (the pressure inside your eye) will be measured.
  • You will be asked to sign a consent form that you are happy for the procedure to take place.
  • You will be given some eye drops before the procedure is carried out to prepare your eye for the laser treatment.

Who will perform the procedure?

The procedure will be performed by a doctor or an appropriately trained allied health professional.

What happens during the procedure?

The procedure takes place in the laser room in the eye clinic. You will be asked to sit in front of a standard eye examination slit lamp and place your chin on the chin rest.

The specialist will insert a contact lens to help improve the view of your eye and to prevent the eye from closing.

A bright white light will be shone into your eye to allow the specialist to see where the treatment is being applied.

When activated the laser used makes a soft beeping noise. The treatment is painless due to the anaesthetic drops used and most people will not experience any feeling in their eye.

What happens after the procedure?

  • You may be asked to wait for 30 to 60 minutes in the waiting room so that your intraocular pressure can be measured again.
  • Eye drops may be prescribed to use after the treatment as instructed by the doctor.
  • You should continue to use your normal glaucoma medication for both eyes unless specifically told not to.
  • A follow up appointment will be arranged for you.

What is the success rate of SLT?

In a study of newly diagnosed patients who had not previously been treated with eye drops, 74% of patients remained free of the need to take eye drops after three years. In a separate study where the majority of patients had previously been on glaucoma medication, success rates were 70% at six months and 45% at 12 months.

The effects of SLT treatment are not permanent but the treatment can be repeated.

What are the risks and side effects of SLT?

Generally, SLT is a very low-risk procedure. There is a small risk that you may experience an increase in eye pressure following the procedure. Your pressure may need to be checked and if needed, a short course of additional medication will be prescribed.

Inflammation can also occur, which this can be treated with anti-inflammatory drops. A prescription for anti-inflammatory eye drops may be issued which can be used if you develop symptoms of inflammation.

There is very small risk of fluid leaking within or behind the retina and also a risk of damage to the cornea. The risk of damage to your vision from either of these is extremely small.

Are there alternatives to SLT?

Patients who choose not to have SLT may be offered the option of starting eye drops or taking additional eye drops if eye drops are used. Certain patients may be offered a surgical procedure to try to control the eye pressure – in these cases the doctor will discuss the risks and benefits of a particular procedure with you.

Patients who choose not to have any of these treatments are at higher risk of developing glaucoma or it worsening, which can cause permanent damage to your vision.