Eye Exam,Glaucoma,Medical Technology

Selective Laser Trabeculoplasty (SLT) is a modern, minimally invasive laser treatment that helps lower eye pressure in patients with glaucoma and ocular hypertension, and it is offered by our glaucoma specialists at North Toronto Eye Care.

SLT (Selective Laser Trabeculoplasty) is a laser procedure that targets the eye’s natural drainage tissue (trabecular meshwork) to improve fluid outflow and lower intraocular pressure (IOP). Unlike traditional surgery, SLT uses low‑energy laser light and does not create cuts, remove tissue, or leave visible scars on the eye’s surface.

Why Lower Eye Pressure Matters

Glaucoma is a chronic, usually silent eye disease that slowly damages the optic nerve over many years, often without noticeable symptoms early on. Elevated eye pressure is one of the main risk factors for glaucoma progression, and reducing this pressure helps protect the optic nerve and preserve vision over time.

Because glaucoma damage cannot be reversed, starting effective treatment as soon as the condition is diagnosed is critical to minimize the risk of permanent vision loss.

How SLT Works Inside the Eye

SLT delivers short pulses of laser energy specifically absorbed by pigment cells in the trabecular meshwork, the main drainage tissue inside the front part of the eye. This laser energy triggers a gentle biological response that “refreshes” the drainage system, allowing fluid to exit more easily and reducing eye pressure.

The laser targets only selected cells, leaving the surrounding tissue structurally intact, which is why SLT is considered “selective” and tissue‑friendly compared with older laser techniques.

SLT as a First‑Line Glaucoma Treatment

Historically, most patients started glaucoma therapy with daily eye drops and were offered SLT later if drops were not enough or caused side effects. More recent evidence shows that SLT can safely be used earlier, and many specialists now consider SLT a first‑line treatment for open‑angle glaucoma and ocular hypertension.

Studies have shown that SLT can provide pressure‑lowering similar to commonly prescribed glaucoma drops, but without the challenges of daily medication use and drop‑related irritation.

Who Is a Good Candidate for SLT?

SLT is generally offered to patients with open‑angle glaucoma or ocular hypertension who have elevated eye pressure and sufficient pigment in the drainage tissue for the laser to work effectively. It may be particularly helpful for patients who struggle with drop schedules, have difficulty remembering medications, or experience side effects such as redness, burning, or stinging.

SLT can also be considered for patients already on drops who need additional pressure reduction, or for those looking to reduce the number of medications when appropriate.

Before SLT, your eye care doctor at North Toronto Eye Care confirms the type of glaucoma, reviews your medical and ocular history, and measures your current eye pressure. You may be asked about allergies and previous medication reactions to tailor your treatment and any drops used around the time of the laser.

In most cases, you can eat and take your usual medications before coming in, and SLT is done as an outpatient visit at one of our Toronto locations.

On the day of SLT, numbing eye drops are placed on the eye, and a special contact lens is gently positioned on the eye’s surface to help the doctor aim the laser accurately at the drainage angle. A series of low‑energy laser pulses are delivered to the trabecular meshwork, typically over 360 degrees, and the treatment for one eye usually takes just a few minutes.

Most patients experience little to no pain; you may notice bright light or a mild tapping sensation but can resume normal activities shortly after the visit unless instructed otherwise.

Right after SLT, your eye pressure may be checked again, and you might receive anti‑inflammatory drops for a short time to reduce temporary inflammation. Mild redness, light sensitivity, or discomfort can occur but are usually short‑lived and manageable.[nshealth]

Your eye pressure is typically monitored at follow‑up visits within the first weeks and months to track the laser’s effect and adjust your overall glaucoma plan if needed.

How Soon SLT Starts Working

SLT does not lower eye pressure instantly; the effect develops gradually over several weeks as the drainage tissue responds to the laser. Many patients show measurable pressure reduction between 4 and 8 weeks after treatment, and your doctor will interpret these readings alongside visual field and optic nerve assessments.[nshealth]

During this period, you may need to continue your existing glaucoma drops until your doctor confirms that the laser effect is stable and sufficient.[glaucoma]

How Long SLT Lasts

The pressure‑lowering effect of SLT is temporary but often long‑lasting, with many patients enjoying benefit for 1 to 5 years before additional treatment is needed. Clinical data suggest that SLT can achieve about 20–25% pressure reduction in a high percentage of patients, though results vary based on individual eye anatomy and disease severity.

When the effect gradually wears off, SLT can be repeated, although the degree of pressure reduction may be smaller with additional sessions and not every eye responds the same way.

Safety and Risks of SLT

SLT is considered a safe, minimally invasive procedure with no cuts, no stitches, and no scarring in the treated drainage tissue. Most side effects are mild and short‑term, including temporary inflammation, slight eye pressure spikes, or transient discomfort, which can usually be managed with drops.

Serious complications are uncommon, but as with any procedure, your doctor will review the benefits and risks with you and monitor your eye pressure closely after treatment.

Booking an SLT Consultation at North Toronto Eye Care

If you have been diagnosed with glaucoma or ocular hypertension, or if you are concerned about your risk, the first step is a comprehensive eye examination with our glaucoma specialists. Our doctors at North Toronto Eye Care can review your test results, explain whether SLT is appropriate for your type and stage of glaucoma, and design a personalized treatment plan.

To learn more or to schedule an appointment for a glaucoma evaluation or SLT consultation, contact North Toronto Eye Care.

References

  1. North Toronto Eye Care. Treatment for Glaucoma – SLT for Glaucoma.[northtorontoeyecare]
  2. North Toronto Eye Care. SLT’s as a first line procedure for the treatment of glaucoma.[northtorontoeyecare]
  3. Glaucoma Research Foundation. Selective Laser Trabeculoplasty (SLT).[glaucoma]
  4. Fraser Valley Cataract & Laser. Glaucoma – SLT information for patients.[fvcl]
  5. GEM Clinic, Winnipeg. Selective Laser Trabeculoplasty (SLT) patient information.[gemclinic]
  6. Nova Scotia Health Authority. Selective Laser Trabeculoplasty (SLT) for Glaucoma pamphlet.[nshealth]
  7. MyHealth Alberta. Laser Trabeculoplasty for Glaucoma.[myhealth.alberta]
  8. North Toronto Eye Care. Treatment for Glaucoma – Eye drops, laser surgery, microsurgery, and iStent information.[northtorontoeyecare]