Below is a narrated animation about ALT and SLT laser trabeculoplasty for glaucoma. Click here to license this video on Alila Medical Media website.
Trabeculoplasty – the Procedure
Trabeculoplasty is a laser treatment for primary open-angle glaucoma. The laser is used to treat the trabecular meshwork, through which the aqueous humor drains. In this procedure:
– The eye is numbed with eye drops.
– A special laser lens is placed on the eye to help control the direction of the laser beams.
– The laser burns a small area in the trabecular meshwork, opening up the drainage canal.
– About 50 spots over 180 degrees of the meshwork circle are treated in one therapy.
Fig. 1: Laser Trabeculoplasty procedure. Click on image to see it on Alila Medical Media website where the image is also available for licensing (together with other related images and videos).
Argon Laser Trabeculoplasty (ALT) and Selective Laser Trabeculoplasty (SLT)
Argon Laser Trabeculoplasty (ALT) : The original laser trabeculoplasty procedure applies argon laser of 514-nm (nano meter) wavelength on half of the meshwork circle in one treatment. Although a second treatment can be performed on the other half of the circle, the procedure is generally not repeatable as it causes extensive scarring of the trabecular meshwork.
The newer technique – Selective Laser Trabeculoplasty or SLT – uses a solid-state (Nd:YAG) laser of 532-nm wavelength. The pulse energy of SLT is about 100 times lower than the traditional argon laser trabeculoplasty. SLT selectively targets pigmented cells while leaving the rest of the trabecular meshwork tissue intact. For this reason, it can be applied to 360 degrees of the meshwork in one treatment and is considered safe to be repeated.
How effective is it?
In term of efficiency, the two techniques return similar results in lowering intraocular pressure. Laser trabeculoplasty treatment is effective in about 75% of patients. The effect may take a few weeks to kick in and can last for several years. Along with pharmaceutical treatments, laser therapy is offered as first-line options for newly diagnosed primary open-angle glaucoma.
