Seasonal affective disorder, or SAD, develops as a result of seasonal changes and is characterized by symptoms similar to clinical depression including sadness, fatigue, difficulty concentrating and irritability. SAD is more common in winter, but summer seasonal depression is also possible. For those with winter-onset SAD, which may be triggered by a lack of sunlight, therapy with a light visor may be helpful.
Technology
Light therapy is done using light that mimics natural sunlight, providing 10,000 lux of light to the wearer. The idea behind using a light visor is to trick the circadian rhythms by providing artificial daylight, thus reducing the sunlight deficiency believed to be behind SAD. Some light visors are made using fluorescent or incandescent lights, while newer models may use LEDs, light-emitting diodes. Other versions of light therapy include light boxes or glasses that aim light onto the eyes.
Use
Someone with seasonal affective disorder who wants to try light therapy using a light visor should wear the cap for about 30 minutes every day. It's perfectly fine to walk around or complete normal activity while wearing the light visor. Patients should begin using the light visor in the fall, before the daylight hours have begun to shorten, and continue daily use through the spring. If stopped too early, SAD may return.
Side Effects
There are few side effects associated with the use of a light visor, and the few side effects that do exist tend to be mild, according to the American Academy of Family Physicians. Some people experience eye strain or headaches as a result of light therapy. Others who use a light therapy visor may find that they become fatigued or irritable. If light therapy is used in the afternoon or evening, it may result in insomnia or an inability to fall asleep.
Considerations
LED-based light visors may be more effective against seasonal affective disorder than other types. Models using narrow spectrum blue light instead of white light also show higher rates of success in treating SAD. In cases where a light visor seems to have no effect, medication may be recommended either in addition to or in place of the light visor.
Warnings
The Food and Drug Administration, or FDA, has not approved light devices such as light visors for the treatment of seasonal affective disorder because clinical trials have seen mixed results about the treatment's effectiveness. According to the "New York Times," some doctors believe that the light emitted by light visors may be too inconsistent to be effective.
