Introduction: Photobiomodulation (PBM) represents a potential treatment for non-exudative age-related macular degeneration (AMD). PBM uses wavelengths of light to target components of the mitochondrial respiratory chain to improve cellular bioenergetic outputs. The aim of this study was to further investigate the effects of PBM on clinical, quality of life (QoL) and anatomical outcomes in subjects with intermediate stage non-exudative AMD.

Methods: The multicenter LIGHTSITE II study was a randomized clinical trial evaluating safety and efficacy of PBM in intermediate non-exudative AMD. The LumiThera Valeda® Light Delivery System delivered multiwavelength PBM (590, 660 and 850 nm) or sham treatment 3 × per week over 3-4 weeks (9 treatments per series) with repeated treatments at baseline (BL), 4 and 8 months. Subjects were enrolled with 20/32 to 20/100 best-corrected visual acuity (BCVA) and no central geographic atrophy (GA) within the central fovea (500 μm).

Results: LIGHTSITE II enrolled 44 non-exudative AMD subjects (53 eyes). PBM-treated eyes showed statistically significant improvement in BCVA at 9 months (n = 32 eyes, p = 0.02) with a 4-letter gain in the PBM-treated group versus a 0.5-letter gain in the sham-treated group (ns, p < 0.1) for patients that received all 27 PBM treatments (n = 29 eyes). Approximately 35.3% of PBM-treated eyes showed ≥ 5-letter improvement at 9 months. Macular drusen volume was not increased over time in the PBM-treated group but did show increases in the sham-treated group. While PBM and sham groups both showed GA lesion growth in the trial period, there was 20% less growth in the PBM group over 10 months, suggesting potential disease-modifying effects. No safety concerns or signs of phototoxicity were observed.

Conclusion: These results confirm previous clinical testing of multiwavelength PBM and support treatment with Valeda as a novel therapy with a unique mechanism of action as a potential treatment for non-exudative AMD.