Light therapy involves exposure to intense levels of light under controlled conditions. The recommended light therapy system consists of a set of fluorescent bulbs installed in a box with a diffusing screen, and set up on a table or desk top at which one can sit comfortably for the treatment session.
Treatment consists simply of sitting close to the light box, with lights on and eyes open.
What is important is to orient the head and body toward the lights, concentrating on activities on the surfaces illuminated by the lights, and not on the lights themselves. Treatment sessions can last from 15 minutes to three hours, once or twice a day, depending on individual needs and equipment used. What appears to be critical is that the level of light produced match that of light outdoors shortly after sunrise or before sunset. The time of day of light therapy is another important factor. Many people with winter depression respond best of all to treatment first thing upon awakening.