Definition & Overview

Trabeculoplasty is an advanced laser-based ophthalmological procedure for the treatment of glaucoma. It improves the eye’s drainage system and reduces intraocular pressure that causes the condition. The procedure comes in two types: selective laser trabeculoplasty (SLT) and argon laser trabeculoplasty (ALT). Although studies show that it is highly effective in treating early primary open-angle glaucoma (POAG), it is considered as either a secondary treatment option or an adjunctive treatment, with the primary (and most widely preferred) treatment option being medical therapy or the use of medications and the last option being surgery.

Who Should Undergo and Expected Results

Trabeculoplasty is a medical procedure for patients with glaucoma, a condition wherein the pressure within the eye builds up to an abnormal level. As a progressive condition, it can eventually lead to a damaged optic nerve, which can cause vision loss or total blindness, especially when left untreated.

Glaucoma presents in several types, namely:

  • Open-angle glaucoma – Considered as the more common form of the condition, open-angle cases account for more than 90% of all glaucoma cases. This problem occurs when the eye canals drain more slowly than normal, causing pressure buildup within the eye before getting released. Although it progresses slowly, the condition will plague a patient for life once it sets in.

  • Angle-closure glaucoma – This is the less common form that occurs when the eye’s drainage canals are blocked. As a result, the pressure is completely barred from being released causing sudden, intense increase in intraocular pressure. This condition tends to progress faster than an open-angle case.

  • Normal-tension glaucoma – This is also called normal-pressure or low-tension glaucoma because the intraocular pressure does not rise significantly but can still cause optic nerve damage over time.

  • Congenital glaucoma – This is usually caused by a developmental problem that hindered the drainage canals from developing fully.

  • Traumatic glaucoma – Some traumatic injuries to the eyes can cause glaucoma either immediately or up to a few years after the injury occurred.
    All these types of glaucoma are primarily treated with medications, while laser trabeculoplasty is more commonly used for the treatment of open-angle glaucoma.

After a successful procedure, patients can expect intraocular pressure to fall to safe and normal levels. ALT achieves this in about 75% of all cases where it is used. Unfortunately, the procedure does not guarantee against future recurrences, which means the pressure within the eye can spike again in the future. In fact, studies show that almost 50% of all patients who undergo trabeculoplasty experience pressure hikes within five years after the procedure is performed. Thus, it is normal for trabeculoplasty patients to continue taking glaucoma medications. In the case of recurrence, they may elect to undergo another laser trabeculoplasty or different surgery depending on the severity of their condition and unique circumstances.

How is the Procedure Performed?

The specific manner in which trabeculoplasty is performed differs depending on which type is used.

In a selective laser trabeculoplasty, short and quick bursts of low-energy SLT laser are sent straight to the pigmented cells embedded inside the eye’s drainage system. The laser energy causes the pores in the eye to grow in size, allowing more fluid to come out and effectively decreasing intraocular pressure in the process. SLT procedures are performed on an outpatient basis and take about two hours to complete, with patients experiencing minimal soreness and a slight pinch sensation when the laser energy is released. While the procedure can effectively lower IOP immediately, the benefits of the procedure will continue to improve within 1-3 months.

In an argon laser trabeculoplasty, the surgeon uses a higher-powered laser, usually a 50-micron spot size beamed within 0.1 of a second, to create tiny burns in the trabecular meshwork to stimulate the drainage holes so they will work more efficiently.

Despite the difference in techniques, both SLT and ALT are effective in reducing intraocular pressure and preventing vision loss. To ensure that pressure is stabilised and to eliminate immediate threat to the patient’s vision, doctors perform an intraocular pressure check an hour after the procedure is performed. If it is still elevated, the patient will receive further treatment the next day, If, however, intraocular pressure is already at normal levels, the patient’s next follow-up visit will be scheduled within 1-2 weeks after the procedure followed by another visit within the next 4-6 weeks and every 3-4 months thereafter.

Possible Risks and Complications

Although complications and side effects rarely occur following a trabeculoplasty, they do pose a certain degree of risk to patients. These complications include:

  • Soreness and redness of the eye/s
  • Blurred vision
  • Elevated eye pressure, or when intraocular pressure rises
  • Peripheral anterior synechiae, or when the iris adheres to the cornea
  • Swelling within the eye
  • Pain
  • Decreased vision
  • Inflammation of the iris
  • Temporary clouding of the cornea
    Furthermore, patients who undergo trabeculoplasty faced an increased risk of developing cataracts, an eye disorder in which the lens become hazy or cloudy.


  • “Laser Surgery.” Glaucoma Research Foundation.

  • Giaconi JA. “Laser Trabeculoplasty: ALT vs SLT.” American Academy of Ophthalmology.

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