A light visor producing constant low light illumination has had mixed results, and was not readily accepted by patients. Of course exposure to natural daylight is highly recommended whenever possible and not surprisingly winter holidays in the sun invariably relieve SAD symptoms. Exercise is also found to be beneficial, but the effects of outdoor exercise may in part result from the accompanying exposure to daylight. Light therapy is used regularly to treat various forms of sleep disorders and is used also to overcome the effects of jet lag and changes in shift-work schedules. Here, the timing of the light therapy is all-important as it is used to accelerate the establishment of the appropriate pattern of melatonin secretion.
Light therapy is used in the morning or before the work shift.
In these applications, oral ingestion of melatonin before going to sleep also helps to reset the circadian rhythm, and is found to be effective in promoting sleep. Disruption of sleep patterns are often observed in the very old and in patients suffering from dementia, with poor links between night-time and sleeping time. It has been suggested that light therapy is effective in restoring the circadian rhythms and the sleep pattern in such patients. One possible explanation for the effect of light therapy in this case may be a result of the increased opacity of the cornea in the elderly. Above the age of sixty, the cornea transmits to the retina less than two thirds of the light which it transmits in young people.