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Selective Laser Trabeculoplasty - an alternative treatment for people with glaucoma


Selective Laser Trabeculoplasty, also known as SLT, is a simple, yet highly effective laser procedure that reduces the intraocular pressure associated with glaucoma.


This laser eye surgery is performed in your ophthalmologist’s clinic, and typically takes no more than 10 minutes per eye.


This article on Selective Laser Trabeculoplasty laser eye surgery is written by Ejaz Ansari, Consultant Ophthalmic Surgeon, Maidstone & Tunbridge Wells NHS Trust, Kent.



How does Selective Laser Trabeculoplasty work?


SLT uses short pulses of low-energy light to target the melanin, or pigment, in specific cells of the affected eye. In response, the body's natural healing mechanisms go to work to rebuild these cells. This rebuilding process improves drainage and lowers intraocular pressure. The surrounding, non-pigmented cells (as well as the rest of the eye structure) are untouched and undamaged.


Doest SLT hurt and are there any side effects?


SLT treatment is painless. Glare and mild discomfort, lasting 3-4 days after the procedure, can occur.


What happens during the procedure?


Prior to treatment, eye drops are administered to prepare the eye and provide mild anesthesia. Then, gentle pulses of light are delivered through a specially designed microscope. The entire process takes just a few minutes. When it's complete, your physician may treat your eye with anti-inflammatory eye drops.  One to three days after the procedure, your intraocular pressure should drop significantly. And of course, your physician will want to re-check the treated eye during periodic follow-up visits. 


How often can I have SLT done?


SLT is gentle, non-thermal and non-invasive - which allows the procedure to be repeated, if necessary. In comparison, repeat treatments of previous approaches in laser therapy were either extremely limited or not possible.


Who will benefit from SLT?


If you fit in to any of the following categories, you're a good candidate for SLT:


  • If you have primary open-angle glaucoma, pseudoexfoliation, or pigmentary glaucoma.
  • If you are intolerant of glaucoma medications, or have difficulty taking them as prescribed.
  • If you are currently undergoing glaucoma drug therapy and wish to combine it with SLT.
  • If it is difficult for you to commit to regular follow-up treatments, lack of transportation, or other limitations.
  • If you have a history of failed ALT (argon laser trabeculoplasty) treatments.
  • If you have had glaucoma surgery and the eye pressure needs further reduction


What if SLT doesn't work for me?


SLT lowers intraocular pressure by an average of 25 percent in 75 to 85 percent of patients treated. For those that do not respond, other forms of treatment, including traditional drug therapy, can still be highly effective. 


Why is it important to relieve intraocular pressure?


The eye's aqueous fluid is constantly produced and drained at a balanced rate to ensure the health and lens of the cornea. When this drainage becomes blocked, intraocular pressure increases and open-angle glaucoma (the most common form of glaucoma) occurs. In order to preserve eyesight, it is critical to decrease and control intraocular pressure.


SLT can be used first line for open angle or narrow angle forms of glaucoma

  • SLT can be repeated safely
  • SLT can be used to augment medical therapy
  • SLT can be used to augment surgery
  • SLT is an outpatient procedure with minimal side-effects

SLT - 10 Compelling reasons 


 1. SLT has been shown to enhance the intraocular pressure lowering effect of medication in many glaucoma patients.

 2. Non-compliance to medications has emerged as the biggest challenge in patient glaucoma management. 

 3. Non-compliant glaucoma patients miss an average of 103.9 days treatment/year. 

 4. A recent study found that 25-40% of glaucoma patients who turned in a prescription at a pharmacy never  picked up the medication.

 5. 42% of glaucoma patients use their medications incorrectly.

 6. At a recent SLT symposium Canadian clinicians reported that when given the option, 70% of patients elected to try SLT treatment in preference to drugs or surgery. 

 7. In a recent study, researchers achieved a 90% success rate using SLT as a primary therapy.

 8. SLT has a much lower complication rate than ALT - a recent study found the complication rate for SLT to be 4.5, in contrast to ALT which has a reported complication rate of 34%. 

 9. At least 70% of failed ALT patients respond to SLT, with a 6.8mm Hg average reduction in IOP.

10. According to international trials, SLT therapy has experienced 80% success in obtaining a mean 23% reduction in IOP, lasting for at least 24 months.

Ansari 60px

Profile of the author

Mr Ejaz Ansari, FRCOphth MD, is an established Consultant Ophthalmic Surgeon and also the Clinical Director for Ophthalmology and Consultant Surgeon for the glaucoma service at the Eye Ear and Mouth Unit, Maidstone and Tunbridge Wells NHS Trust. He specialises in Glaucoma laser and surgical techniques, early glaucoma diagnosis, laser refractive surgery and small incision day-case cateract surgery. He is also a Senior Lecturer at the Department of Physical Sciences, University of Kent at Canterbury.


View a profile of Ejaz Ansari

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