Harvard Women's Health Watch

Ask the doctor: Can a light box for SAD damage my eyes?

Q. I suffer from seasonal affective disorder (SAD) and want to try using a light box. Should I be concerned about damage to my eyes?

A. Light therapy can be effective for SAD. However, you should use the treatment under the supervision of an experienced professional. Light treatment usually consists of exposure to a light source from a 10,000-lux box for 10 to 15 minutes per day at first, gradually increasing to 45 minutes 1–2 times per day. Your eyes should remain open throughout the treatment session. Damage to the eye's retina is a theoretical risk, but it has not been found to be a problem thus far. Nevertheless, you should take precautions to get your dose of light as safely as possible.

To help protect your eyes, do not stare at the light source during your treatments. Use fluorescent light rather than incandescent, because the former disperses light more broadly than a smaller focused incandescent source. Use a fixture with light dispersion or screens that filter ultraviolet rays to help protect your eyes. Although light boxes can cost between $200 and $500, and insurance may not always pay for them, it is best to buy a commercially available one rather than build one yourself.

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