SLT laser for glaucoma: what it is, who it suits and how long it lasts

How it works

Fluid inside the eye drains out through a tiny filter at the edge of the iris, called the trabecular meshwork. In open-angle glaucoma this drain works less well. SLT uses brief, low-energy laser pulses on the meshwork to help it drain better. It does not burn or scar the drain, which is why it can be repeated.

What happens on the day

You are given numbing drops and sometimes a drop to stop a pressure spike. You sit at a laser machine like the one used for eye examinations, and a special contact lens is held on the eye. You may see flashes and hear clicks. It usually takes a few minutes per eye. Your pressure is checked afterwards. Most people go back to normal activity the same day, though the eye may ache a little.

The pressure-lowering effect builds over some weeks, so you will be asked back to check whether it has worked.

Who it suits

It is not the treatment for narrow-angle glaucoma, which uses a different laser, or for some secondary glaucomas. Your eye doctor decides after examining the drainage angle.

• Newly diagnosed open-angle glaucoma or high eye pressure
• People who find drops hard to use, remember or afford
• People with side effects from drops
• As an add-on when drops alone are not enough

Its limits

Not everyone responds. In those who do, the effect often fades over the years, and it can be repeated or drops added. You still need regular glaucoma checks for life, whether or not you use drops afterwards.

Common questions