Using Light Boxes

Light Therapy

Many doctors confidently prescribe “light therapy” as an alternative treatment to anti-depressant medications. Light therapy involves regular exposure during “low-light” times to artificial light which simulates sunlight.

The size, shape and construction of light therapy boxes will vary. The type of bulbs or screens used to emit the SAD light will also vary. The important commonality is that all light therapy boxes emit strong light that simulates natural sunlight.

Light Therapy Exposure Times

As with direct sunlight, you do not look directly into the light box. Rather, the light therapy box is placed so that light reaches the eyes indirectly. Recommended light therapy exposure times will vary depending on the doctor, the severity of symptoms and the effectiveness of prior experimental exposure times. However, in general, recommended exposure to a 10,000 lux light therapy box is a half hour. If a patient has difficulty with the intensity of the light from such a box, a weaker light—as low as 2,500 lux—may be used for a longer period (in this case, two hours).

Night Shift

For many, an increase in the sleep-inducing melatonin along with a decrease in serotonin causes SAD. Other factors besides the change in seasons may also cause light deprivation and depression; for instance, those who work nights and sleep days, or those who travel internationally for business and experience jet lag, may also have these symptoms of depression as exposure to sunlight becomes limited.


When you first begin light therapy, you may want to start with shorter duration of use. Your doctor can also recommend a treatment schedule for you; generally, you begin with shorter blocks of time, usually 15 minutes. You will gradually increase your light therapy by five minutes until you reach at least 30 minutes per day. You can use the light box for daily sessions ranging from 30 minutes to two hours, depending on your need. Though evening, or morning and evening, use of light therapy may be effective for some, using light therapy close to bed time often causes difficulty sleeping. 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.


A positive response usually begins 2 to 4 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. Light therapy is usually continued on a regular schedule until exposure to natural sunlight becomes regularly and readily available.



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