SLT fares best as early intervention in glaucoma

Selective laser trabeculoplasty (SLT) can be used at a variety of intervention points in the treatment of glaucoma. The effect varies, depending on the treatment history of the patient.

A study of SLT as primary therapy was conducted in Israel and published in Archives of Ophthalmology in 2003. In the study, IOP decreased by 30%; 89% of the eyes had a decrease of ≥5 mm Hg. This is similar to the effectiveness reported for latanoprost (Xalatan, Pfizer Ophthalmics). The authors concluded that SLT is safe and effective as a primary treatment for patients with ocular hypertension and open-angle glaucoma.

Even in diseased eyes, SLT can offer good-and occasionally dramatic-results. I think it is worth considering at any stage of the disease process, depending on the unique circumstances of each patient. It appears that SLT is most effective at reducing IOP when used as primary therapy or in conjunction with fewer medications.

Presently, the most common first-line therapy for glaucoma is one of the prostaglandin analogues: latanoprost, bimatoprost ophthalmic solution (Lumigan, Allergan), or travoprost ophthalmic solution (Travatan, Alcon Laboratories Inc.). These drugs are an improvement over beta blockers for many patients, but they are not without side effects. Hyperemia and permanent iris color change may occur with use, and some patients find such side effects unacceptable.

Moreover, there are some important psychological factors that come into play once you tell patients they have glaucoma and will have to take action every day to treat it. Just knowing that they have a potentially blinding disease can have a subtle negative effect on patients' quality of life. This is one reason it is worth considering alternatives to daily treatment such as SLT.

Patients' compliance with their medication regimens is a complex issue. Some patients are in denial. They see no symptoms, don't believe that they have glaucoma, and do not want to take medications. Others have complicated dosing schedules for other conditions that make the addition of another medication, even at once-a-day dosing, problematic.

In terms of compliance, we have to be concerned with whether patients actually administer the therapy as prescribed and whether they continue to use the therapy over time. The former is difficult to measure. One of the major drug manufacturers is looking at the latter issue-what one might term persistence-by analyzing prescription refills. If it is confirmed that those are reliable numbers, we may be able to use these data as a surrogate marker for compliance as well as tolerability. Regardless, if compliance is a concern, SLT is an ideal approach. When the laser works, compliance is simply not an issue.

Finally, economic issues also can affect ophthalmologists' ability to keep treating patients with a medication long term. SLT is generally at least partially covered by insurance and, therefore, may be less expensive to the patient over time than medication. Indeed, it can be particularly hard to convince patients whose insurance does not cover their medication to spend money to treat a disease that is asymptomatic in the early stages.

Secondary therapy Here are a few examples of patients from my own practice who benefited from SLT as a secondary therapy.