Photobiomodulation Therapy for Non-exudative Age-related Macular Degeneration.

Abstract

Age-related macular degeneration (AMD) is a chronic condition that causes gradual central vision loss, most commonly in patients 50 years or older. This disease is commonly classified as either dry (non-exudative) or wet (exudative). Most patients with AMD have the non-exudative form, characterized by the presence of drusen in the macula. These patients can be further subclassified based on drusen size into early, intermediate, or late stages. The pathogenesis of this disease is quite complex and has been linked to genetic variations, dysfunction of normal retinal homeostasis, chronic inflammation, and mitochondrial dysfunction. Current treatment options for patients with intermediate dry AMD are limited to lifestyle modifications and vitamin supplementation. Photobiomodulation therapy (PBT) has been proposed as an additional therapy for this disease. Early animal and human studies have shown that PBT can alter many of the pathways implicated in the pathogenesis of AMD including improving mitochondrial function, decreasing inflammation, and promoting wound healing. Clinical trials investigating the use of PBT in patients with non-exudative AMD have shown promising results. Many of these trials showed improvement in both clinical (visual acuity and contrast sensitivity) as well as anatomic (drusen volume and area geographic atrophy) variables. Most, however, are limited by sample size, differences in treatment algorithm, and populations tested. Ongoing clinical trials aim to expand on this work with longer follow-up, larger sample sizes, and studying a global population. Further work is needed to determine ideal treatment algorithms and patient populations that may benefit the most from this technology.