What you can expect

By Mayo Clinic Staff

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Starting light therapy

Generally, most people with seasonal affective disorder begin treatment with light therapy in the early fall, when it typically becomes cloudy in many regions of the country. Treatment usually continues until spring, when outdoor light alone is sufficient to sustain a good mood and higher levels of energy.

If you typically have fall and winter depression, you may notice symptoms during prolonged periods of cloudy or rainy weather during other seasons. You and your doctor can adjust your light treatment based on the timing and duration of your symptoms.

If you want to try light therapy for nonseasonal depression or another condition, talk to your doctor about how light therapy can be most effective.

During light therapy

During light therapy sessions, you sit or work near a light box. To be effective, light from the light box must enter your eyes indirectly. You can't get the same effect merely by exposing your skin to the light. While your eyes must be open, don't look directly at the light box, because the bright light can damage your eyes. Be sure to follow your doctor's recommendations and the manufacturer's directions.

Three key elements for effective light therapy

Light therapy is most effective when you have the proper combination of duration, timing and light intensity:

  • Duration. When you first start light therapy, your doctor may recommend treatment for shorter blocks of time, such as 15 minutes. You gradually work up to longer periods. Eventually, light therapy typically involves daily sessions ranging from 30 minutes to two hours, depending on your light box's intensity.
  • Timing. For most people, light therapy is most effective when it's done early in the morning, after you first wake up. Your doctor can help you find the light therapy schedule that works best.
  • Intensity. The intensity of the light box is recorded in lux, which is a measure of the amount of light you receive at a specific distance from a light source. Light therapy boxes usually produce between 2,500 lux and 10,000 lux. The intensity of your light box affects how far you sit from it and the length of time you need to use it. A 10,000-lux light box usually requires 30-minute sessions, while a 2,500-lux light box may require two-hour sessions.

Finding time for light therapy

Light therapy requires time and consistency. You can set your light box on a table or desk in your home or office. That way you can read, use a computer, write, watch TV, talk on the phone or eat while having light therapy. But stick to your therapy schedule and don't overdo it.

Some light boxes are even available as visors that you can wear, although their effectiveness isn't proved.

Mar. 20, 2013