Selective laser trabeculoplasty

Selective laser trabeculoplasty (or SLT) is a simple laser procedure for glaucoma that can be performed in the eye clinic. It is used to lower the intraocular pressure in suitable patients. It can be used as an alternative to regular long-term use of eye drops or as an adjunct when eye drops are not lowering the eye pressure enough.

What is SLT and how does it work?

In SLT, micro-pulses of laser energy is applied to the drainage tissue inside the eye. This laser energy is specifically designed to target the pigment cells in the drainage tissue, and causes a biological reaction and healing response in the tissue. Th ultimately improves the passage of fluid through the drain and lowers the intraocular pressure. However it may take 1-3 months for the desired effect to fully appear. 

What happens during the procedure?

The laser is delivered via a microscope similar to those used for eye examination. Prior to the treatment, several eye drops are instilled to prepare the eye for the procedure. During the procedure, the laser will appear as pulses of light applied to the eye via a special lens that rests on the eye. The entire procedure takes less than 5 minutes to perform, and is generally painless. Mild aching sensation may seldom occur after the procedure, but invariably resolves within 24 hours. 

Who will benefit from SLT?

Patients with 'open-angle glaucoma' who are in need of lower intraocular pressure to slow down their glaucoma progression are eligible for the procedure. SLT is particularly useful in the following clinical situations:

What are the risks?

A key aspect of SLT that makes it a particularly good treatment option for many patients is that it has a very favourable side effect profile. SLT is generally considered very safe with relatively minor occasional side effects such as transient intraocular pressure spikes that can be managed by glaucoma medications and usually resolve within 24 hours. Significant side effects of SLT are very rare. 

How effective is SLT?

SLT is able to lower intraocular pressure by 25-30% in about 75% of patients receiving the treatment. In those who responds well to the laser, the effect is comparable to that of commonly used glaucoma medications. Pressure-lowering effects of SLT generally last between 1- 5 years. SLT can be repeated in those who have had a good response to their first treatment. However, the success of subsequent treatments may be less predictable. 

What happens if it doesn't work?


In those whom SLT fails to lower intraocular pressure to the desired amount, other means of glaucoma treatments such as addition of medications or surgery can still be used. The fact that one has had the laser does not affect the success of other subsequent treatment modalities. 

Will I still need glaucoma medication after SLT?

The use of SLT can be thought of as being equivalent to a single glaucoma medication. Whilst some patients can be sufficiently treated with laser alone, others may need laser plus one or more glaucoma medications; in the same way as some patients who require multiple glaucoma medications. It is important to remember that whatever method is used to treat glaucoma, the aim is to primarily slow down its progression rather than as a cure. It is therefore crucial to ensure that there is ongoing follow-up examination and testing to monitor the progress of the disease.

Dr Joshua Yuen

Dr Joshua is an experienced consultant ophthalmic surgeon, who specialises in retinal diseases and cataract surgery... read more

Dr Brad Johnson

Dr Johnson is an experienced consultant ophthalmic surgeon, who specialises in retinal diseases and cataract surgery... read more