SLT viable option in treating primary open-angle glaucoma

Selective laser trabeculoplasty is as productive as medications, less invasive than surgery and more cost-effective, surgeon says.

Paolo Lanzetta

UDINE, Italy — Selective laser trabeculoplasty should be offered more frequently as a primary option in treating primary open-angle glaucoma, according to one surgeon.

Less invasive than surgery, SLT is at least as effective as medications — but has fewer drawbacks — and is more cost-effective and deserves “a better place in the therapeutic choice,” OSN Europe Edition Board Member Paolo Lanzetta, MD, said.

The range of glaucoma medications has broadened remarkably in the past 2 decades, with the obvious consequence of making medical management the preferred first line of therapy in the majority of patients, Dr. Lanzetta said. SLT, which gathered the interest of glaucoma specialists about 10 years ago, was soon relegated to niche therapy, with only a small number of advocates.

“Medical therapy is perceived as simpler, safer and definitely less traumatic, but drawbacks and failures are often underestimated,” he said.

Drawbacks with medications

Compliance with medications is poor in more than one-third of the patients, as shown by several studies, and increasingly so when more than one medication a day is prescribed.

“Poor compliance is a complex issue, difficult to predict and rectify. Inevitably, it leads to insufficient and inconsistent IOP control and, eventually, to disease progression,” Dr. Lanzetta said.

Medications also have numerous systemic and local adverse events, and are well-known to reduce the success rate of future surgical procedures when needed.

SLT uses Nd:YAG laser energy to selectively target pigmented trabecular meshwork cells with low threshold radiant exposures without producing collateral thermal damage to adjacent non-pigmented cells or structures.

“It is a minimally invasive procedure that has shown in several studies to produce a significant reduction of IOP in the immediate postoperative period, with hardly any complications. Results have been shown to remain stable over time,” he said.

The procedure is fast — about 5 minutes — and cost-effective. A recent study by Cantor and colleagues showed that laser trabeculoplasty techniques, including SLT, offered a potential cost savings of about $1,700 for patients who need two to four medications over 5 years.

“The study calculated that the 5-year cumulative costs of [laser trabeculoplasty] were approximately $4,838, compared to the $6,571 of medications and $6,363 of filtration surgery,” Dr. Lanzetta said.

Laser system with YAG ability

Since 1998, Dr. Lanzetta has been using SLT in more than 100 patients.

“Although numbers are still limited, we are satisfied with our results,” he said.

He has been using different machines, and in the past year, he has adopted the new Ellex Tango laser system for SLT with added YAG capabilities.

“The Tango features a proprietary dual-mode laser cavity, specifically designed to make procedures as effective as possible,” Dr. Lanzetta said.

The machine features a high level of precision, in which parameter settings can be adjusted at 0.1 mJ increments.

“This capability, coupled with superior energy control and with a high, 3 Hz repetition rate, allows a fast and highly accurate delivery of SLT treatment and enables the physician to tailor treatment to the individual patient’s response,” he said.

Additionally, the Tango’s built-in slit lamp converging optics provides a clear, user-friendly and natural stereoscopic viewing of the anterior segment.

“It’s a compact, efficient design that creates more working space for the physician, as well as convenient, simultaneous access to the patient and laser controls,” Dr. Lanzetta said.

As with other SLT systems, Tango has added YAG capabilities.

“I use it regularly for my YAG capsulotomies, and this makes the investment definitely worthwhile,” he said. – by Michela Cimberle

Reference:

• Cantor LB, Katz LJ, Cheng JW, Chen E, Tong KB, Peabody JW. Economic evaluation of medication, laser trabeculoplasty and filtering surgeries in treating patients with glaucoma in the U.S. Curr Med Res Opin. 2008;24(10):2905-2918.

• Paolo Lanzetta, MD, can be reached at the University of Udine, Department of Ophthalmology, Piazzale S. Maria della Misericordia; 33100 Udine, Italy; +39-0432-559-905; fax: +39-0432-559-904; e-mail: paolo.lanzetta@uniud.it. Dr. Lanzetta has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.

The author is undoubtedly right in asserting that SLT should be used as primary therapy of open-angle glaucoma in those patients who are willing to undergo this simple procedure. The foremost reason for this statement, as he appropriately writes, is that in most cases, poor compliance makes medical therapy of glaucoma less effective than laser or surgical therapy. The literature on noncompliance in glaucoma is voluminous, describing measurements of the phenomenon in various ways such as electronic monitoring, prescription refill records, container inspection and direct interviews. Most of those investigations indicate that, as stated in a recent review on the subject, rates for persistence are generally below 50% at 1 year (Schwartz and Quigley. Surv Ophthalmol. 2008;53:S57-S68).

It seems that noncompliance is a major, apparently insurmountable, problem preventing the effective anti-ocular hypertensive drugs from reducing patients’ IOP adequately on the long run. Thus, the 60% to 70% efficacy of SLT, which lasts for a few years and is probably repeatable, is apparently superior in controlling IOP in open-angle glaucoma. When one adds to this consideration the practical lack of permanent side effects of SLT (there are less than 10 such side effects reported in the literature) and the monetary saving afforded by this modality to the patient and community, one can hardly understand what prevents more ophthalmologists from adopting SLT as first-line therapy of open-angle glaucoma.

– Michael Belkin, MA, MD
Sidney A. Fox Professor of Ophthalmology, Tel Aviv University, Israel

• Prof. Belkin is a consultant to Ellex.