Affiliations: [a] Department of Ophthalmology, University of Zürich, Switzerland | [b] Institute for Lighting Engineering, Free University, Berlin, Germany | [c] Department of Psychiatry, Columbia University, and New York State Psychiatric Institute, New York, NY, USA
Correspondence:
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Correspondence: Dr. Ch.E. Remé, Department of Ophthalmology, University of Zürich, 8091 Zürich, Switzerland. Tel.: +411 255 3672; Fax: +411 255 4438. Supported by the Swiss National Science Foundation grant – Nr. 3100–040791.94/1 and Wilhelm-Sander-Stiftung, Munich, Germany (Ch.E.R.) and U.S. National Institute of Mental Health grant # RO1 MH42931 (to M.T.).
Abstract: In recent years, bright light treatment of seasonal affective disorder (SAD), recurrent depressions in fall and winter, has been discovered. Newer applications include circadian sleep phase disorder, shift work and jet lag. Apart from creating the visual signal, light can modify retinal structure and physiology. UV and visible light lead to distinct lesions of ocular tissues under certain experimental und naturalistic conditions. In light therapy, a large variety of fixtures is used but the spectral emission of lamps is mostly unknown to the user and clinician leading to the potential hazard of ocular lesions. Therefore, we have analyzed a wide selection of light sources commonly used for treatment. We measured the spectral emission and calculated irradiant doses for several light therapy regimens. Based on these measurements, potential hazards are analyzed, physiological mechanisms of light action are discussed and safety measures for bright light therapy are proposed. They include recommendations for lamps devoid of damaging spectral emissions and standardized therapy fixtures, ophthalmological monitoring of patients with eye diseases and control by optometrists for patients with healthy eyes who are likely to undergo light treatment for extended periods.
