Selective laser trabeculoplasty is a laser treatment used in open angle glaucoma and ocular hypertensive patients.
An increase in the intraocular pressure occurs due to a problem in the drainage of the fluid or aqueous humour from the eye. Thus there is a build-up of the fluid in the eye leading to increased intraocular pressure. This increased intraocular pressure causes damage to the optic nerve that leads to progressive and irreversible vision loss and if untreated may lead to blindness. The blockage can be due to closure of the opening of the drainage canal (closed angle glaucoma) or the clogging can be inside the canal (open angle glaucoma). Selective laser trabeculoplasty is used only for open angle glaucoma.
In this treatment modality laser is applied to the drainage angle which is like a meshwork. Short pulses of low energy laser light are targeted against the specific cells, the pigmented trabecular meshwork cells. The laser energy is absorbed selectively more by the pigmented cells than by the non-pigmented cells of the trabecular meshwork thus leaving the non-pigmented cells unaffected by the thermal damage and the coagulative damage. Moreover the pulse or the time of the laser is so low that heat produced in the pigmented cells may not spread to the non-pigmented cells of the meshwork. The procedure can be repeated, if required and comparatively safe.
The pigmented cells release the dark pigment melanin and activate the natural immune system’s scavenger cells- macrophages which eat up the obstructive proteins and clear the channels.The fluid is then more effectively drained and intraocular pressure is released.
The procedure is non-invasive and done as an outpatient procedure. The eye drops are added to the eye to numb the area. The laser is used on the eye. The whole procedure takes only few minutes. The anti- inflammatory eye drops are administered and the patient is sent home. The discomfort may also go within 3-4 days.
Advantages of using SLT:
- The side effects observed are minimal as compared to other laser procedures and surgical treatments.
- It is an outpatient procedure requiring only one or two sittings per eye.
- It can be used as a primary treatment or used with medications for intraocular pressure reduction.
- It is a better treatment modality for patients with poor adherence or poor tolerance with intraocular pressure reduction medications.