SLT effective part of glaucoma care strategy in developing countries

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Selective laser trabeculoplasty provided a majority of Afro-Caribbean patients with a mean IOP reduction of 40% with no need for medical therapy.

By Lynda Charters; Reviewed by Tony Realini, MD, MPH

Morgantown, WV-Selective laser trabeculoplasty (SLT) may prove beneficial to patients with glaucoma in the African-derived developing world, as part of a research program to identify cost-effective strategies for glaucoma care.

“The magnitude of IOP reduction following SLT is significant, on the order of 35% to 40%,” said Tony Realini, MD, MPH, associate professor of ophthalmology, West Virginia University Eye Institute, Morgantown, WV. “This result is at least as good as-and perhaps better than-the results expected with a prostaglandin analogue.”

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The St. Lucia Study

In a prospective cohort study of the effects of SLT in open-angle glaucoma (OAG) in an Afro-Caribbean population from St. Lucia, most patients realized a decrease in IOP of 40% that was sustained over 3 years, without medical therapy, Dr. Realini said.

Sixty-one patients with OAG who were taking one glaucoma medication were included in the study. After a 30-day washout period, baseline IOP was determined in two measurements and patients were treated with bilateral 360° SLT. Patients were followed after treatment at 1 hour, 1 week, 1 and 3 months, and every 3 months thereafter through 36 months.

NEXT: SLT rationale + Photo

When patients enrolled in the study, the average IOP values in the right and left eyes, respectively, were 17.3 ± 5.0 and 17.5 ± 4.0 mm Hg on medical therapy, and 21.4 ± 3.6 and 21.1 ± 3.5 mm Hg after washout.

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At the 36-month evaluation, 21 patients’ responses to treatment had been censored or deemed failures, and 40 patients’ responses to treatment were considered successes, with no further interventions after the initial SLT.

The mean IOP reduction in the 40 subjects at 36 months was 8.3 ± 3.2 and 8.3 ± 3.6 mm Hg in the right and left eyes, respectively.

This represented an average 37% IOP reduction from baseline in both eyes, Dr. Realini noted.

Five patients in whom the initial SLT treatment failed underwent another SLT treatment and four of these patients re-established IOP control with no medications. Ultimately, 44(72%) patients remained controlled on no medications after one or more SLT treatments.

The SLT rationale

“People of African descent have a much higher prevalence of glaucoma, about three- to five-fold higher, compared with patients of European descent,” Dr. Realini said. “The prevalence rates in African countries and Afro-Caribbean countries are about 8% to 10% compared with roughly 1.8% in the United States.

“This is coupled with limited resources to treat glaucoma and prevent the all-too-common visual impairment and blindness that occurs in many developing nations,” he added.

NEXT: Conclusion

Addressing glaucoma with daily instillation of eye drops in a developing country is impractical because of extreme poverty. The average income in St. Lucia, where the study was conducted, is one-tenth that of the United States, he said.

In light of these complications, Dr. Realini and his colleagues have been seeking a care strategy that acknowledges the limitations of the region, but also provides the most efficacious and safe therapy for glaucoma.

“Laser has always been attractive, but argon laser trabeculoplasty-the predecessor to SLT-could not be repeated safely and when the laser effect wore off, the IOP returned to the pre-treatment level,” he explained.

SLT may provide a longer-term solution for glaucoma based on several reports documenting its safe and effective repeatability.

Some questions, however, have risen about its use:

> How long do the effects of SLT last before re-treatment is needed?

> Is a repeated treatment as effective as the initial SLT treatment?

Though SLT is not necessary be a “one-shot approach,” it may be a “long-term strategy for treating glaucoma,” Dr. Realini said.

Additionally, SLT is more convenient and more practical than 3 years of medical therapy. The cost-effectiveness of SLT and the absence of compliance problems are among its biggest benefits, Dr. Realini said.

References

• Avery N, Ang GS, Nicholas S, Wells A. Repeatability of primary selective laser trabeculoplasty in patients with primary open-angle glaucoma. Int Ophthalmol. 2013;33:501-506. doi: 10.1007/s10792-013-9729-3. Epub 2013 Jan 31. PubMed PMID: 23371484.

• Hong BK, Winer JC, Martone JF, Wand M, Altman B, Shields B. Repeat selective laser trabeculoplasty. J Glaucoma. 2009;18:180-183. doi: 10.1097/IJG.0b013e31817eee0b. PubMed PMID: 19295367; PubMed Central PMCID: PMC2714284.

Tony Realini, MD, MPH

e:realinia@wvuhealthcare.com

This article is adapted from Dr. Realini’s presentation at the 2014 meeting of the Association for Research in Vision and Ophthalmology. Dr. Realini has no financial interest in the subject matter. Lumenis provided the laser used in the study.