Reduced risk of CNV after SDM laser retinal protective therapy

The dry form of age-related macular degeneration (AMD) is the most common type of the disease, but successful treatments have been elusive in patients, resulting in disease progress and visual loss.

Subthreshold diode micropulse (SDM) laser as retinal protective therapy (RPT), an investigational laser treatment and a specific form of micropulse laser, might be a step in the quest to help patients with this form of the disease.

The technology was found to improve retinal and vision function in dry AMD, according to Jeffrey Luttrull, MD, in private practice in Ventura, CA, and developer of the therapy. The recognition of its success led to a question about whether SDM can reduce progression of dry AMD to wet AMD. 

Beginning in 2014, Dr. Luttrull and colleagues conducted an observational retrospective cohort study in which they reviewed the electronic medical records database of all active patients in one private vitreoretinal practice who had been treated with SDM RPT for dry AMD. The patients were classified according to the Age-Related Eye Disease Study (AREDS 2) categories of severity and all included patients had AREDS 2 or greater in at least one eye. The primary study endpoint was the development of new choroidal neovascularization (CNV) after treatment.

All study eyes were treated with an identical panmacular treatment technique with identical laser parameters with no titration of the laser treatment, according to Dr. Luttrull.

The investigators identified 392 patients who were eligible for the study, and, ultimately, the treatment was offered to 95% of those who were eligible. The treatment was elected by 97% of those who were offered the treatment and the actual number of study patients was 354 (547 eyes), after 2% of treated patients were lost to follow-up. All patients were followed for an average of almost 2 years.

The median patient age was 84 years. All patients took the AREDS vitamin supplement.

Visual acuity

“Importantly, the chart visual acuity remained unchanged, that is, was stabilized, throughout this study, which was quite different from untreated eyes that lost visual acuity,” Dr. Luttrull said.

Another important finding was that new CNV developed in less than 1% of treated eyes.

“The eyes in which new CNV developed were actually those of patients who were slightly younger than the average in the study,” he said.

A significant risk factor for development of new CNV was found to be reticular pseudodrusen.

The patient acceptance of SDM is extraordinarily high, according to Dr. Luttrull.

“They actually seek out the treatment,” he said. “It is an easy treatment and there is an absence of other available treatments. Early treatment and shorter treatment intervals might improve results.”

This study comprised a large group of eyes that were at high risk of progression of dry AMD. However, with treatment, the chart visual acuity was stable and the risk of conversion to wet AMD was low.

“The treatment is quick, simple, and safe,” Dr. Luttrull emphasized.

“In a high-risk population, SDM RPT markedly reduced the risk of new CNV in dry AMD and stabilized visual acuity without adverse treatment effects,” Dr. Luttrull said. “SDM RPT may offer a new, safe, and highly effective method of reducing the risk of vision loss in patient with dry AMD.”

A multicenter trial is planned to begin in 2018.

Dr. Luttrull has a financial interest in this technology. He presented his results at the 2017 meeting of the American Society of Retina Specialists in Boston.