Glaucoma can sometimes be treated successfully with medications to lower the pressure inthe eye. If medications are not effective, laser and other surgical procedures could be of value in controlling the pressure and preventing further vision loss. Both medications and surgery are designed to do one of two things:
- Decrease the amount of fluid production in the eye from the cells that make the fluid
- Help the fluid flow out of the eye
Selective laser trabeculopasty (SLT) is one option for lowering intraocular pressure (IOP) for patients who have open-angleglaucoma in the early stages. It can also be used in combination with drug therapy or as an alternative therapy when drugs fail. It is a flexible treatment option and can be repeated if necessary, depending on the individual patient's response.
How it works
The trabecular meshwork is around the periphery of the iris and is where fluid formed in theeye drains out of the eye. This meshwork is treated directly with the laser to improve drainage through it.
SLT uses short pulses of relatively low- energy light to target only the melanin- rich cells inthe drainage channel of the eye. The laser pulses affect only these melanin containingcells, with the surrounding structure remaining unaffected. This gentle laser treatment induces a response from the body in which white cells are released to clear the affectedcells and rebuild the meshwork so that it functions effectively again, reducing the IOP.
Benefits
SLT effectively lowers raised IOP without the side effects or difficulty of taking eye drops.The treatment is particularly suitable for patients who cannot correctly use or are intolerant to glaucoma medications, and can also be used alongside medication to enhance the overall IOP-lowering effect.
SLT is a newer form of a long- established treatment that has the advantage of not causing any damage to the tissue treated.
The treatment procedure
Treatment takes place in the outpatient department. A nurse will check your vision and putsome drops in your eye to prevent the pressure rising and to make your pupil small. Thesedrops might cause a temporary headache and can take up to one hour to work. A doctor will take your written consent and if you have any questions, will explain further.
Once seated in front of the laser machine, which looks similar to the microscope you will have been examined with in clinic, you will have anaesthetic drops put in to numb the frontof your eye. A special lens will then be placed against the front surface of your eye. This is not painful, but it might feel a little strange. During the laser treatment, you might see some flashes of light and hear clicking noises. Most patients tolerate the laser treatment well, butsome might feel slight discomfort. The procedure takes between 10 and 15 minutes.
About an hour after your treatment, the pressure in your eye will be checked. You will then be given a prescription for drops to take at home for five days. We will make anappointment for you to come back to the clinic, usually one to two weeks later. This follow-up appointment is to check that your eye is settling, although the treatment might take up to eight weeks to work.
Potential side effects
Your vision will be blurred for a few hours following your laser treatment, but this will settle.The chance of your vision being permanently affected from SLT is extremely small. If youare concerned that your vision is not returning to normal, please contact us on the numbers below. You are also advised not to drive yourself to the hospital, as you will beunable to drive home.
It is possible for the pressure in your eye to increase immediately after the treatment and for there to be inflammation. In order to prevent this, we put in special drops whenwe treat you.
We also provide steroid drops, and occasionally extra glaucoma drops following your treatment.
Rarely, the pressure in the eye rises to a very high pressure and does not come down. If this happens, you might require surgery to lower the pressure. However, please be assured that this is a very unusual occurrence.
Success rate
Studies show a 78% success rate for SLT, with some patients responding well to the treatment, but others not responding at all. Usually, we cannot predict how well the laserwill work.
This is because your response is determined by the type of glaucoma you have and thebasic make-up of your eye.
If you take eye drops, you will usually need to continue these to lower the pressure afterlaser trabeculoplasty. It will take up to eight weeks after the laser treatment for thepressure to be reduced. You might require additional laser surgery to lower the pressure ifit is not at a sufficiently low level after your first laser treatment.
The effects of the laser treatment might wear off in time – about half of all treatments stopworking after five years. However, the treatment can be repeated.
Contact for further information: Please contact the main switchboard on 020 7253 3411and ask to speak to your consultant’s secretary.
Author: Emma Jones and Gus Gazzard, glaucoma department
Review date: March 2020