Exploratory crossover field study indicates efficacy and feasibility of light therapy glasses to mitigate fatigue in...

Fatigue is highly prevalent, clinically significant, and persistent in multiple sclerosis (MS), highlighting the need for effective countermeasures. To evaluate the feasibility and efficacy of blue-enriched bright light (BL) therapy glasses in reducing MS-related fatigue, this single-blind, randomized, active-controlled crossover study included 20 patients with MS with significant fatigue (Fatigue Severity Scale [FSS] total score > 36). Participants used blue light (BL) glasses or dim red light (DRL) glasses for 20 min daily after waking. Each intervention lasted 1 week with a 6-day washout between conditions. Fatigue, measured using the FSS four times per intervention week, was the main exploratory outcome measure. Further, the acute overall effects of both interventions were assessed using a Visual Analogue Scale for Fatigue (VAS_F) immediately before and after each intervention and at 13:00. Quality of life (Multicultural Quality of Life Index) was rated four times per week. Feasibility was evaluated using self-reported comfort, side effects, and sleep quality. Both interventions significantly decreased total FSS scores on the sixth and seventh intervention days (follow-up), with BL inducing clinically significant reductions on the sixth day. Both interventions significantly reduced VAS_F ratings immediately after the intervention and at 13:00, with BL showing significantly more reduction. No effects on quality of life were observed. Patients reported greater comfort, improved well-being, and reduced fatigue with the BL glasses. Side effects were low and subjective sleep quality was unaffected. Despite its small sample size, the present exploratory study provides initial evidence for light therapy glasses as a feasible, immediately effective intervention for MS-related fatigue.