Bright light therapy: Minimizing light induced side effects with an innovative light setup

Abstract Objective. Bright light therapy (BLT) is regarded to be an effective treatment against seasonal depression (SAD). Conventional BLT devices are reported to evoke few, but inconvenient symptoms. This study evaluated side effects associated with a new technology for BLT in a healthy population. Methods. In an uncontrolled study design 20 healthy Caucasians received 30 min light exposures on three consecutive mornings. Immediate side effects were evaluated using questionnaires. The new light cabin was equipped with fluorescent lamps (light colour 965 = 6,500 K, CRI >90) with a maximum illumination of 5,000 lux and a maximum luminance of 1,500 cd/m(2). Occurrence of headache was determined to be the main objective. Results. Nineteen volunteers completed the study. No headache was reported at any time. With a prevalence of 21.1% blurring was observed to occur more often after light exposure. Conclusion. With the evaluated light cabin the most prominent short-term side effects of BLT can be minimized, enhancing patients' adherence.