Chapter 9
The Biological and Therapeutic Effects of Light
George C. Brainard Department of Neurology, Jefferson Medical College, Philadelphia, PA, USA
9.1 Introduction
Light can be a potent biological and therapeutic force. Light is fundamental to life on the planet earth. Without radiant energy from the sun, the earth would be a frozen rock in space unable to support sophisticated life processes. It stands to logical reason that specific physical qualities of light, wavelengths or their color appearance, for example, would be intricately involved in life processes. While this seems to be a very basic idea, unanswered questions abound. What physiological responses are most responsive to the spectral quality of light? Which specific wavelengths ...
