Multiwavelength photobiomodulation in atrophic age-related macular degeneration.

Purpose: To evaluate photobiomodulation (PBM) safety and efficacy in patient with atrophic AMD and to explore tissue effects using Spectrally Resolved Autofluorescence (SrAF) to identify a potential biomarker indicative of mitochondrial activity, the primary PBM target.

Methods: This retrospective, non-comparative case series involved six eyes of five patients with atrophic AMD, conducted at the Medical Retina and Imaging Unit, IRCCS San Raffaele Hospital in Milan, Italy. At baseline and follow-ups (after one and three months) a complete ophthalmological assessment and multimodal imaging, including spectrally resolved autofluorescence (SrAF), were performed. PBM treatment (Valeda Light Delivery System - LumiThera) was administered in nine sessions over three weeks. The SrAF images were analyzed to evaluate the effect of the treatment.

Results: Six eyes of five patients with atrophic AMD received PBM at baseline. Best corrected visual acuity (BCVA), mean central macular thickness (CMT), mean retinal sensitivity on microperimetry and the atrophic area have remained stable. No eyes developed foveal atrophy after the treatment. The image analysis in SrAF showed an increase in the highlighted area of 4.89% after one month and 17.11% after three months. No adverse systemic or local side effects were reported.

Conclusion: PBM is a safe treatment for the human retina. The evaluation of the retinal area within the green light spectrum (575 nm) in SrAF is a potential indirect biomarker of mitochondrial activity and could be used to assess treatment efficacy in clinical studies.