Light has several well-proven uses in medicine. Regular sessions with e.g. white light are an excellent remedy for the “winter depression” known as seasonal affective disorder. Ultraviolet light is frequently used in the treatment of psoriasis.
Natural light is a potential remedy for jaundice in newborns. And, for all of us, sunlight is a leading source of vitamin D.
How the Treatments Are Done :
Seasonal Affective Disorder Treated With Pure White Light Bright light therapy is the treatment of choice for seasonal affective disorder (SAD). The “white” lights used in these treatments match the radiation you would get from natural sunlight shortly after sunrise or before sunset, but do not contain any ultraviolet wavelengths. To receive any benefit from this therapy, you must keep your eyes open during the entire session.
Ranges from 15 minutes to 3 hours, depending on the brightness of the light source.
Therapy usually begins in the fall and lasts until early spring. It is best to have your sessions in the early morning or at dusk. One session per day is usually sufficient, although some therapists recommend twice-daily sessions for the first few days, or until your condition improves. You can probably take an occasional day off without any problem.
If you are receiving light therapy for skin conditions such as psoriasis or vitiligo, your doctor will probably give you a drug called psoralen 1 or 2 hours before your session. During therapy, your entire body will be exposed to ultraviolet light. A series
of 30 sessions is usually required over a period of 10 weeks. (A similar approach to skin cancer, using light-activated drugs, is currently under investigation.) For jaundice in newborns, intense full-spectrum light (or sunlight) is the recommended treatment. Full-spectrum lights, which are now being installed in many offices, factories, and other workplaces, have also been recommended for ailments ranging from migraines to premenstrual syndrome, but have yet to beconclusively proven effective for anything but jaundice.
In one form of therapy, the practitioner directs light at a specific part of your body with a quartz-tipped “crystal flashlight.” In another, you sit under a bulb that diffuses colored light around you. Each session will last approximately 25 minutes. The time needed for other forms of light therapy varies widely. For localized pain, one practitioner recommends 2 five-minute applications of red light to the site, followed by 10 to 15 seconds of light on the area around it. You’ll receive 2 or 3 treatments daily for the first week, Therapy with Light then twice daily sessions for a second week.
What the Treatment Hopes to Accomplish.
Light has been used as a medicine for millennia. In the 6th century BC, Charaka, an Indian physician, treated a number of diseases with sunlight. Hippocrates and other ancient Greek physicians had their patients recuperate in roofless buildings,
where they could soak up the rays of the sun. By the 1890s, European sanatoriums were prescribing incandescent electric “light baths” to treat many physical and psychological conditions, and Niels Finsen, a Danish physician, was using ultraviolet light to treat tuberculosis. Light therapy as we know it today appeared in the 1980s, when doctors realized that people deprived of light sometimes developed symptoms such as depression, lethargy, inability to concentrate, and difficulty sleeping. Researchers speculated that the problems stemmed from a disruption of the patient’s circadian rhythm, an internal 24-hour “dark-light cycle clock” that governs the timing of hormone production, sleep, body temperature, and other functions. Circadian rhythm is regulated by the pineal gland, which, in turn, is controlled by the presence or absence of external light. During the first hours of darkness, the pineal gland produces the hormone melatonin, a substance that promotes sleep and, according to some researchers, may even strengthen the immune system.
When you disturb the circadian rhythm by sleeping during the day, traveling across time zones, or getting insufficient exposure to light, your health begins to suffer. The two most striking examples of the phenomenon are jet lag and seasonal
affective disorder (SAD). SAD strikes 4 to 6 of every 100 people, most of them women over 20 years of age, although children also develop the disorder. The victims, who usually live in northern climates, generally feel fine during the spring, summer, and early fall, when the days are long, but become sleepy, gain weight, crave carbohydrates, and grow unhappy as the days get shorter. Some develop insomnia, lose their sex drive, grow irritable and moody, and find it impossible to complete tasks. Children may become hyperactive or have problems learning and concentrating. To reset the body’s internal clock, researchers tried giving SAD patients regular doses of full-spectrum or bright white light from late autumn to early spring. They
speculated that the extra light would suppress overproduction of melatonin (the suspected cause of SAD) and keep the melatonin cycle “in time with the real world.” This theory was never substantiated, but the success of the treatments—for
Whatever reason—was indisputable.
Other experiments with light therapy have not, unfortunately, worked out as well. Light has been tried for a wide variety of ailments. Colored light can eliminate problems in different parts of the body—for example,
that flashing opaque white or violet light can reduce stress and relieve pain; or that red light can remedy ailments ranging from endocrine problems to depression, impotence, headaches, stomach aches, and diabetes. Colored beams striking the eyes are supposed to regulate various body functions by stimulating corresponding areas of the brain. The latest researches have shown, that e.g. red light stimulates the endocrine hormones, that our skin is sensitive to react on light. When light enters the eye, brightness- and color-sensitive cells in the retina convert it to electrical impulses that travel up the optic nerve to the brain. According to one theory, these impulses stimulate the hypothalamus, the region of the brain that regulates such automatic functions as sleep, body temperature, digestion, moods, sexual function, and the immune system. Other theories suggest that light may affect other parts of the brain, such as the cerebral cortex, which governs creativity, learning, and memory; the cortex, which governs movement; and the brain stem, which controls balance. Critics of light therapy point out that none of
the theories have been scientifically verified, and dismiss the whole issue. Scientists also reject the claim that too much artificial light and too little natural light prevents the body from absorbing adequate nutrients. (Advocates of light therapy charge that sunglasses, windows, and pollution are reducing our exposure to the full spectrum of natural sunlight, and that indoor lighting—usually about 500 lux—is insufficient to compensate for the loss of the 50,000 lux supplied by sunlight.) Although it’s clear that exposure to sunlight increases the body’s supply of vitamin D—a necessity for healthy teeth and bones—critics say that its benefits stop there.
Who Should Avoid This Therapy?
Light therapy is not advisable if your skin or eyes are highly sensitive to light. Avoid it, too, if you have any type of manic-depressive disorder. If you are taking any medications, you might want to check with your doctor or pharmacist before beginning light therapy. A wide variety of drugs can increase your sensitivity to light.
What Side Effects May Occur?
Overexposure to ultraviolet rays can cause skin cancer and may contribute to premature aging of the skin. Other possible side effects of light therapy may include a “hyper” feeling, mild headache, trouble sleeping, sore eyes, and other eye problems.