SLT equals medication results?

February 2, 2013

New data are complicating debates over the relative utility of selective laser trabeculoplasty (SLT) compared with medication. “We have been taught to start with medication, then move on to laser trabeculoplasty, then consider filtering surgery if all else has failed,” said L. Jay Katz, MD, director of glaucoma at the Wills Eye Institute and professor of ophthalmology at Thomas Jefferson University, Philadelphia.

San Francisco-New data are complicating debates over the relative utility of selective laser trabeculoplasty (SLT) compared with medication.
    
“We have been taught to start with medication, then move on to laser trabeculoplasty, then consider filtering surgery if all else has failed,” said L. Jay Katz, MD, director of glaucoma at the Wills Eye Institute and professor of ophthalmology at Thomas Jefferson University, Philadelphia. “It is time to consider laser as a primary treatment. We already know it doesn’t work well following medication failure.”
    
Clinicians should consider four factors in designing first-line therapy, he explained during a CME Symposium at Glaucoma 360 on Saturday. The key elements are efficacy at lowering IOP, patient adherence, safety, and cost.
    
A 1995 study comparing argon laser trabeculoplasty with timolol (then the medication of choice for glaucoma) found similar results between the two treatments, about a 50% reduction in baseline IOP. The results looked good, he said, but failed to change clinical practice because of various objections to the trial design. Investigators randomly assigned eyes, not patients, which led detractors to suggest the drug affected both eyes.
    
After prostaglandin analogues became first-line therapy, a small pilot trial comparing medication with laser found a 30% reduction in IOP from baseline. Larger trials in the United States, Canada, and the United Kingdom comparing prostaglandin analogues with SLT found similar reductions from baseline IOP.
    
The laser treatment produced transient spikes in IOP but few other common side effects. Medication produced the expected constellation of cosmetic, ocular, and systemic adverse events.
    
Adherence clearly favors laser, Dr. Katz noted. Even when medications are free, nearly half of patients report taking less than 75% of prescribed glaucoma medications.
    
“Our best guess is that 50% to 75% of patients are compliant,” he said. “With laser, you have 100% compliance.”
    
Studies also suggest a cost-effectiveness advantage to laser. Medications are more costly in the long run despite the appearance of generic prostaglandin analogues because of the impact of patient non-adherence.
    
“Using SLT is a reasonable choice for some patients,” he concluded. “There is a similar reduction in IOP as medication and safety, compliance, and cost may tip the decision toward laser trabeculoplasty.”

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