Conficting Info on Selective Laser Trabeculoplasty

Selective Laser Trabeculoplasty (SLT) is becoming a very widely used glaucoma treatment. Some eye clinics are making fantastic sounding claims for the procedure.

Here is a quote directly off a respected eye clinic's web site:

SLT offers you the following benefits:

  • SLT is simple, safe, and effective glaucoma treatment for almost 100% of our glaucoma patients.
  • SLT only takes minutes to perform in the office for your convenience.
  • SLT is NOT painful and there are no restrictions or limitations after the office treatment.
  • SLT is very successful and you may only need one treatment to replace the daily use of expensive drops.
  • SLT does NOT involve any needles, knives, sutures or hospital surgery.  Risks and complications are almost zero.
  • SLT is covered by almost every insurance company, including Medicare.
  • SLT is ideal for patients who want to get off their glaucoma medicines, cannot take them, cannot afford them, or tolerate their side-effects.
  • SLT is a cold laser that does not cause scarring or damage like all previous laser treatments in the past.  This lets it be repeated safely, if needed.
  • SLT has been safely done in Europe for over 10 years and can keep glaucoma controlled 365 days a year for up to 5 years.
  • SLT is also a safe alternative for those not controlled with previous laser surgery or eye drops or pills.
  • SLT has no systemic side-effects (all eye drops have side-effects).
  • SLT tries to eliminate the high costs and side-effects of prescription medicines, eye drops and dangerous invasive surgery treatments used in the past.
  • SLT is the ideal treatment for people over 40, African-Americans, Hispanic-Americans, and those with diabetes, high blood pressure or poor circulation.
  • SLT is FDA approved and uses patented technology.
  • SLT promotes the body's own natural healing response and reduces any chance for bleeding, infection, or blindness.

"Thousands of our glaucoma patients have already received this SLT therapy.  It is proving to be simple, safe, and effective at controlling glaucoma pressure and preventing blindness.  The use of the SLT laser treatment has been found to lower the eye's pressure in almost 100% of our patients and improve the control of glaucoma."

How accurate are these claims? I will examine just a few of them in more detail.

SLT is simple, safe, and effective glaucoma treatment for almost 100% of our glaucoma patients.

An October 2005 study showed high failure rates. By the end of the study, the failure rates were 86% or 92% (depending on the definition of failure). The study was based on 94 patients. The reference is:

Journal of Glaucoma. 14(5):400-408, October 2005.
Song, Julia MD; Lee, Paul P MD, JD; Epstein, David L MD, MMM; Stinnett, Sandra S DrPH; Herndon, Leon W Jr. MD; Asrani, Sanjay G MD; Allingham, R Rand MD; Challa, Pratap MD

Other studies have shown much higher success rates. It is not clear why there is this disagreement. However, there is some indication SLT works better in patients over a certain age (either over 50 or over 60).

There is also some indication SLT works better in some types of patients than others. For example, one small case study arrived at the following conclusion:

This case series suggests that post-SLT IOP elevations can be a serious adverse event in some glaucomatous patients. It is recommended by the authors that patients with a deeply pigmented trabecular meshwork, taking multiple topical medications and having previous ALT treatment, should be considered at higher risk for this complication

(I don't see how their lawyers let them put "Risks and complications are almost zero" on the web site. Isn't that inviting a law suit?)

SLT is very successful and you may only need one treatment to replace the daily use of expensive drops.

A more balanced claim is given on the web site of the Glaucoma Research Foundation:

Q: Will I still need to continue using my eyedrops following the SLT procedure?
A: Maybe. Each individual is different. Although there is a chance you can eliminate or reduce medications, SLT cannot guarantee this.

Another study reported that only 72.4% of patients did not require medications after SLT. That isn't bad, but it is not 100%.

  • SLT tries to eliminate the high costs and side-effects of prescription medicines, eye drops and dangerous invasive surgery treatments used in the past.

    What this says to me is that we will not really understand all the problems associated with SLT until it has been around longer. Each of the "dangerous invasive surgery treatments used in the past" was hailed as a newer, more effective treatment when it was introduced. Some have track records that I don't think are that great. Of course SLT really does seem like an improvement over other techniques. But when I first started reading about it, it sounded like a panacea. (After all, when a highly respected eye clinic makes the claims we are examining here, if one doesn't look a bit deeper, it really does sound like a miracle cure.) The research tells me that SLT is not 100% safe and effective. I don't think we'll really know how safe it is for another 10 years (giving it a two decade track record in Europe).

  • SLT is FDA approved and uses patented technology.

    I'm supposed to be impressed that SLT uses patented technology? Come on!

  • SLT promotes the body's own natural healing response and reduces any chance for bleeding, infection, or blindness. 

    This is another claim that insults one's intelligence. How do they think the body heals from any surgery? The body's own healing response is what makes the incision heal.

    In the case of SLT, there is no incision. But certain cells are destroyed by the laser. The immune system is thought to clean up some of the burned (called "collateral thermal damaged" in some literature) cells. Here is one explanation of how it works (and notice how they make it sound so nice):

    "When treated with SLT, a primarily biologic response is induced in the trabecular meshwork which involves the release of cytokines that trigger macrophage recruitment and other changes leading to IOP reduction."

    My conclusion: SLT does show promise. I'm considering SLT for myself. I wish it was as miraculous as some of the eye clinics make it sound, but it isn't. I'm wondering if we'll see sites for SLT like we have seen for Lasik one of these days. I hope not. And I also hope that if I have SLT, all goes well.

    My first step will be to find an expert physician who tells it to me straight.

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In a single-surgeon study of

In a single-surgeon study of glaucoma patients with uncontrolled IOP on maximally tolerated medical therapy, argon laser trabeculoplasty (ALT) was associated with a greater IOP-lowering effect than selective laser trabeculoplasty (SLT), reported Bryce Ford, MD.

Retrospective single-surgeon study suggests ALT superior to SLT