Low-Level Nighttime Light Therapy for Age-Related Macular Degeneration: A Randomized Clinical Trial

To investigate the safety, acceptability, and effectiveness of light therapy on the progression of AMD over 12 months.

This was a phase I/IIa, prospective, proof-of-concept, single-center, unmasked randomized controlled trial. Sixty participants (55 to 88 years) with early AMD in the study eye and neovascular AMD (nAMD) in the fellow eye were recruited from a hospital nAMD clinic. Eligible participants were randomized (ratio 1:1) to receive light therapy or to an untreated control group. Light therapy was delivered via a light-emitting mask (peak 505 nm, 23 scotopic Td), which was worn each night for 12 months. Co-primary outcome measures were disease progression (onset of nAMD or increased drusen volume beyond test-retest limits) and change in time constant of cone dark adaptation. Other main outcomes included adverse events, compliance, and subjective sleep quality data.

Disease progression over 12 months was seen in 38.1% (18.1%-61.6% confidence interval [CI]) of intervention participants and 48.3% (29.4%-67.5% CI) of controls (Mantel-Haenszel test, common odds ratio = 0.763, P = 0.495). A significantly larger delay in cone adaptation was observed in the intervention group (1.66 ± 0.61 minutes) than in the control group (0.66 ± 0.49 minutes) over the follow-up period. No reported adverse events were deemed to be associated with the intervention.

Although acceptable to the patients, light therapy did not have a substantial effect on the progression of early AMD over 12 months. Further investigation is necessary to discover the permanency and cause of the adverse effect of light therapy on dark adaptation.