Clinical and ocular safety

Clinical safety

The Society for Light Treatment and Biological Rhythms has established safety standards for light therapy. Lightboxes that adhere to these standards are very safe to use and long-term studies have shown no negative side effects. Researchers also report that short-term side effects are benign and better tolerated than side effects experienced with anti-depressant medications. These side effects are usually mitigated within the first week of therapy, or by increasing the distance or duration of exposure. Patients rarely stop using light due to side effects. The most common side effects are nausea, headaches, jitteriness, and eye irritation.

Ocular safety

The primary concern with bright light therapy is the potential for ocular damage. In both short and long-term studies, no ocular abnormalities have been found. When safety guidelines are followed in the manufacture of light therapy devices, the risk of ocular damage is minimal. Safe lightboxes will incorporate parabolic reflectors and UV filtered lenses to produce a safe, diffuse field of light. The level of irradiance lightboxes produce is approximately 1/10 th that of noonday sun, without the harmful UV and dark blue radiation.

Photosensitizing Medications

In general, the photosensitizing risk with medications is usually with ultraviolet light. However, because of the potential risk that such medicines pose, light therapy should not be used with any photosensitizing medications, such as certain antibiotics, anti-depressants, skin medications, diuretics and hypoglycemics.

Contra-indications

Patients who experience mania should be stabilized under a physician's care before receiving light therapy. (Lithium should be cautioned as a mood stabilizer as it may be photosensitizing). Also certain photosensitizing medications should not be used with light. Melatonin is often used in conjunction with light therapy, but it is also photosensitizing and should only be taken at night when light is not used. Some herbal remedies such as St. John's Wort (Hypericum perforatum), may have photosensitizing effects.

Of particular concern, anyone with preexisting eye problems should undergo a thorough examination prior to and during light therapy. Eye conditions such as diabetes mellitus or retinopathy, macular degeneration, or retinitis pigmentosa are contra-indicated for light therapy.