research digest
Studies Show SLT Effective as Both Primary, Secondary Therapy

Two separate studies show that selective laser trabeculoplasty (SLT) is effective as primary therapy, and a third study demonstrates that as secondary therapy, SLT's efficacy can offer the benefit of reduced need for medications to maintain lower IOPs.  

A study published in the April 2006 issue of the Journal of Glaucoma demonstrates that SLT is as effective as latanoprost for first-line and adjunctive IOP-lowering in patients with newly diagnosed open-angle glaucoma. Ian McIlraith, M.D., and colleagues performed a prospective multicenter nonrandomized 100-eye clinical trial, in which patients chose to receive either SLT or latanoprost. In a secondary arm to the study, a different group of patients who were intolerant or unresponsive to medical therapy received SLT to test its efficacy. Patients were treated and followed for a total of 12 months, with checks at the 1-, 3-, 6- and 12-month time points.

Of 100 eyes enrolled (61 patients total), 74 received SLT and 26 received latanoprost. The mean IOP reduction for those who underwent SLT was 8.3 mm Hg (31.0%), vs. 7.7 mm Hg (30.6%) for patients taking latanoprost (P=0.28 [P=0.879]). Eighty-three percent of patients responded with a 20% IOP reduction with SLT, compared with 84% of patients on latanoprost. Angle pigmentation caused no differences in IOP lowering with SLT and there was a slight contralateral effect on non-treated fellow eyes with SLT.

The study concluded that, over 12 months, SLT was as effective as latanoprost for first-line reduction of IOP in patients with newly diagnosed open-angle glaucoma and ocular hypertension.

ARVO Study

In a study presented at the 2006 Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting, Lawrence F. Jindra, M.D., and Arucha Gupta, M.D., also showed that SLT is effective as a primary treatment for reducing IOP in patients with glaucoma. The study relied on retrospective chart reviews of patients who, between January 2002 and January 2005, received SLT for lowering IOP. Charts were reviewed for 474 of 1,029 eyes that had SLT. Retrospective review was conducted on the IOP for 60 of those eyes for 3 years every 6 months, noting any retreatment with SLT or medical intervention.

The average decrease in IOP from the 474 eyes studied was 35%, or 7 mm Hg, ±3.2 mm Hg (from 20.4 mm Hg [±4] to 13.4 mm Hg [±3.3] [P<.0001]). The average decrease in pressure for the 60 eyes was 31.2% (1 year), 33.6% (2 years) and 34.3% (3 years). The gross failure rate for SLT as primary therapy in the 474 eyes was low at 5.9% and net failure was even lower at 0.7%. The researchers concluded that SLT was effective for the patients in this study as both primary and long-term therapy for lowering IOP in glaucoma.

"We can now offer patients newly diagnosed with glaucoma a state-of-the-art, repeatable cold laser treatment that can control their IOP and preserve their vision without sentencing them to the lifetime rigors and discomfiting side effects of daily topical medications," says Dr. Jindra.

Secondary Therapy

Arusha Gupta, M.D., and Lawrence F. Jindra, M.D., conducted another study that was presented at the 2006 ARVO Annual Meeting and evaluated the efficacy of selective laser trabeculoplasty for secondary therapy for lowering IOP and its effect on the number of medications that patients must take to maintain low pressures. The retrospective study reviewed 433 eyes from 1029 eyes in medical charts from January 2002 to January 2005 and utilized two-tailed t-tests to compare IOP and number of medications used before and after SLT procedures.

For the eyes studied, the average decrease in IOP was 6.5 mm Hg (±6.2), or 30% (from 21.9 mm Hg [±6.4] to 15.4 mm Hg [±5.5]). Medications were reduced by an average of 1.3 (±1.1), or by 63% (from 2.1 [±0.9] to 0.8 [±1.0]). Both the reduction in IOP and the number of medications required by patients were significant (P<.0001).

The researchers also found that after SLT was used as a secondary treatment, a gross control rate of 77% (one medication or none used for maintenance) was reported in long-term follow-up, which was 259 days. No medications were needed to control IOP for a net control rate of 54%. In conclusion, SLT was found to be effective for secondary treatment in patients with glaucoma and in reducing the number of medications to maintain therapeutic IOP.

"For patients on multiple topical glaucoma medications that may be ineffective and/or causing life-debilitating side effects, SLT is a definitive treatment that we can offer to control their IOP and take the issue of daily compliance off the treatment table," Dr. Jindra says.