Bright light therapy consists of sitting close to the light box with eyes open so the light shines on the user’s face. Looking directly at the light is not necessary. One is free to read, write or eat a meal while staying oriented towards the light.
Sitting within the 10,000 lux range, or 24 inches for a 30-minute session soon after awakening is enough time, and equals sitting in the 2,500 lux range or at about 40 inches for a two hour session. Intensity levels are changed by moving towards or away from the light. Treatment can last between 15 minutes to three hours. Once adjusted to light therapy, one gets a fairly good intuitive feel for adjusting the session length to get the desired results.
A positive response usually begins two to four days after beginning light therapy, and it could take up to several weeks to get the full beneficial effect. If patients do not respond to treatment, they may need a longer duration of morning light, or a trial of evening light. Some people can skip treatments for one to three days, occasionally longer, without ill effects, but most have symptoms returning quickly when treatment is interrupted.