Selective laser trabeculoplasty is a surgical procedure that employs the use of a laser to lower intraocular pressure (IOP). The disease is among the leading causes of preventable blindness worldwide. It occurs when prolonged high IOP impairs the optic nerve, which sends visual images to the brain, leading to irreversible vision loss and blindness.

SLT is often used as a secondary treatment when glaucoma medication such as eye drops and pills, have significant side effects, or are not sufficiently reducing the eye pressure. It can also be employed as the initial glaucoma treatment.

SLT is an advancement over the previous non-selective lasers such as Argon laser trabeculoplasty (ALT), and has been used effectively and safely in treating some forms of glaucoma over two decades. However, it's essential to realize that the treatment can only slow or stop glaucoma progression and loss of vision, but it doesn't cure glaucoma. Its effectiveness also usually wears off after some time.

Also Known As

  • SLT


Preparation & Expectation Before Surgery

During the consultation before the treatment, the patient can seek clarification on the procedure, benefits, risks, etc. The surgeon will take a detailed patient medical history, conduct a comprehensive eye examination, and review any medication the patient may be taking. The patient should disclose all medications and dietary supplements that they are using. The patient should also be accompanied by someone or make arrangements to be taken home after the procedure, mainly where both eyes will be treated.

Types, Purpose & Procedure

The SLT procedure is a smart, safe, selective and non-invasive technique that improves the eye's drainage channel without affecting the surrounding structures. It utilizes an advanced cold laser system to precisely target specific pigmented cells of the trabecular meshwork, the eye's drainage tissue. It causes the microscopic pores in the trabecular meshwork to expand, which improves the flow of the aqueous humor, and lowers IOP.

SLT is an outpatient procedure conducted in the eye surgeon's office or an outpatient surgery center. A technician will check the patient's eye pressure and administer eye drops to constrict the pupil and prevent an IOP spike after the treatment. The patient will be escorted to the laser room where the surgeon will apply anesthetic eye drop(s) on the eye(s) to numb them. S/he will then position the patient in the laser machine and place a specialized microscope on the eye surface. The treatment lens is coated with a special jelly to focus light into the eye better.

The surgeon will direct the laser to the edge of the iris to treat the trabecular meshwork. The patient will hear a series of clicks and see red light flashes as the laser targets the drainage tissue. The patient will also feel the subtle movement of the treatment lens on their eye surface during the operation. The procedure usually takes five to ten minutes per eye.

After the surgery, the patient is escorted to the waiting area. The eye pressure will be rechecked in 30 to 60 minutes, and if it's stable, the patient will be released to go home.

Risks, Side Effects & Complications

In rare cases, the patient may experience:

  • Eye pain
  • Headache
  • Inflammation
  • Corneal edema
  • Inflammation of the iris
  • Conjunctival inflammation

SLT surgery has no systemic or allergic side effects. The patient may experience a mild sensation during the operation, and increased light sensitivity and blurring of vision for several hours after the operation. The symptoms usually disappear within 24 hours.

About five percent of the patients may experience a temporary increase in IOP after the treatment.

After Care, Recovery & Results

The surgeon will prescribe topical anti-inflammatory drops for the patient to apply as soon as they get home. The patient should also continue taking all of their glaucoma medications as prescribed. S/he may want to see the patient the day after the surgery to check the IOP and follow up in one to four weeks, depending on the patient's status.

Generally, the patient may resume regular activities after the treatment without any restrictions. The temporary rise in IOP following the procedure is usually managed by glaucoma medications and resolves in 24 hours.

The full effects of the surgery can be apparent in one to two months after the treatment. SLT is considered a success when the results last for at least six months. In most cases, the effects can last between one and five years, after which the treatment wears off. The surgery can be repeated, but repeat operations may not be as effective in lowering the IOP as the initial treatment.