Bright white LT has been shown to reduce fatigue in other neurological disorders.

Adults 18-70 years old with MS fatigue were randomized 1:1 to 10,000 lux bright white light (BWL, active) or <300 lux dim red light (DRL, control).

Participants enrolled for 10 weeks in a 2-week baseline of sleep/fatigue tracking; a 4-week intervention of twice daily 1-hour LT; and a 4-week washout without LT. An EDSS and MS Quality of Life-54 (MSQOL-54) inventory were recorded.

Primary outcome measures were the feasibility of LT and occurrence of adverse events (AEs).  Change in FSS and MSQOL-54 from baseline to the end of LT were analyzed.

141 patients were screened. 41 enrolled. 6 patients voluntarily withdrew before study procedures. 4 withdrew during LT.

There were 35 participants (28 female;mean age 44.9;median EDSS 3.0) in the intention to treat analysis with a mean baseline FSS of 52.7 (range 37-63). 20 participants received BWL and 15 DRL.

There were 15 AEs with BWL (headache 8; difficulty sleeping 3; dizziness 1; difficulty seeing at night 1; fatigue 1; hot flush 1) compared to 3 with DRL (headache 1; eye strain 1; tearing issues 1). 4 AEs were related to prior conditions.

The post-LT mean FSS did not differ between BWL and DRL (mean 45.8 vs. 46.7 points). The mean change in FSS from baseline was -6.5 for BWL vs. -6.7 for DRL (p=0.95).

The mean change in MSQOL-54 from baseline was 7.1 for BWL vs. 4.7 for DRL (p=0.57).