NEW YORK (NYT) -- For people who become depressed when the days grow short, a condition called seasonal affective disorder, one treatment is to sit in front of bright light for an hour or more each day. But a common complaint of patients is that they do not have time to do that regularly.
One solution is to have patients wear light visors, with either incandescent or white light-emitting diodes (LEDs) under the brims. That lets the patients move around while they get extra light, but some doctors question the effectiveness of the visors, saying the light exposure is inconsistent.
One company, Enlightened Technologies Associates, based in Fairfax, Va. (www.etai.com), says it has developed special glasses, called Somnavue, that can deliver light therapy more effectively to people who need it. Light therapy is also used to help people with sleep disorders and jet lag, in additional to those with seasonal affective disorder.
The glasses are attached by a fiber-optic bundle to a Walkman- size box, worn on the belt or in a pocket, containing battery- powered LEDs. They produce light that goes through the fibers to the eyeglasses' frames, at the back of the ears. The light moves through the frame to six optical fibers that ring the middle of each lens. Each fiber is linked to its own red, green or blue LED, and they aim light at the pupil at angles that get light to the periphery of the retina without interfering with vision, or being obvious to other people.
Light therapy is thought to be effective for conditions like seasonal affective disorder or jet lag because light is the most powerful environmental cue for setting the daily biological rhythms, called circadian rhythms, that affect things like hormone, sleep and mood cycles.
Light exposure signals an area of the brain called the suprachiasmatic nucleus, a cluster of cells near the spot where the optic nerves cross. The brain sends information about light to the pineal gland, which is at the base of the brain and produces a hormone called melatonin, which helps regulate circadian rhythms. …