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Light
and colour have been valued throughout history as sources of healing.
Today, the therapeutic applications of light and colour are being
investigated in major hospitals and research centres worldwide.
Results indicate that full-spectrum, ultraviolet, coloured, and
laser light can have therapeutic value for a range of conditions
from chronic pain and depression to immune disorders and cancer.
Uses
Light has several
well-proven uses in medicine. Regular sessions with a light box
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. The list of ailments that light will not cure
is, unfortunately, much longer. Despite claims to the contrary,
there is no scientific evidence that light-coloured or otherwise-will
cure cancer, arthritis, menstrual problems, Alzheimer's disease,
high blood pressure, headaches, hyperactivity or AIDS. There is
also little reason to believe that light will reduce stress, cure
jet lag, relieve insomnia, improve fertility, speed healing, boost
immunity, reduce cholesterol levels, increase the amount of oxygen
in the blood or stimulate the thyroid gland.
Procedure
of Treatment
Seasonal
Affective Disorder: Bright light therapy is the treatment of
choice for seasonal affective disorder (SAD). The 'white' lights
used in these treatments match the radiation would get from natural
sunlight shortly after sunrise or before sunset, but do not contain
any ultraviolet wavelengths. Most people take the treatments at
home, although some receive therapy in an office or clinic. If you
are being treated by a therapist, you may be asked to lie on a couch
under a lamp that emits at least 2,500 lux of illumination-about
half the brightness of full sunlight. To receive any benefit from
this therapy, you must keep your eyes open during the entire session.
For home treatments,
you will probably be advised to buy a light box. Most of these devices
measure approximately 2 feet by 2 feet and enclose a full-spectrum
or bright white light that is angled toward your face. While most
of these lights are 2,500 lux, some may be as bright as 10,000 lux.
If you do not wish to purchase a light box, you can use any high-intensity
fluorescent lamp that does not emit ultraviolet rays. Place the
box on a table or other flat surface where it is level with your
eyes. You should sit about 18 inches from the box, facing the light
source, but never looking directly at the bulb. (Some manufacturers
recommend that you sit farther away. Be sure to read the directions
on your box.) During the treatment session, you can read, eat, work,
watch television or perform other activities, as long as you remain
facing the light with your eyes open. (If you need to move around
during the sessions, you might want to buy a light visor powered
by rechargeable batteries.) Never wear sun glasses or goggles during
treatment.
Treatment Time: Ranges from 15 minutes to three hours, depending
on the brightness of the light source. If you use a 2,500-lux source,
you will need two hours per session. A 5,000-lux light requires
30 to 90 minutes; a 10,000-lux source, 25 to 45 minutes.
Treatment Frequency: 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.
Other Conditions: If you are receiving light therapy for
skin conditions such as psoriasis or vitiligo, your doctor will
probably give you a drug called psoralen one or two 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 be conclusively proven effective
for anything but jaundice.
For a wide variety of other conditions, ranging from pain to glandular
problems, some physicians advocate treatments with coloured light.
There is no scientific proof that such treatments will work, but
if you decide to experiment, you will have several options. 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 coloured light around you. Treatments
dubbed 'syntonic optometry employ specialized machines such as a
Lumatron® to flash coloured light into your eyes at the rate
of 2 to 16 beams per second. If you are being treated with a Lumatron,
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 will receive two or three treatments daily for the first
week, then twice daily sessions for a second week.
Benefits
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
in 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, travelling 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 four to six
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,
but with little documented success. For example, one Israeli study
claimed to show that a light-tipped probe inserted into the nasal
passages of allergy patients could provide at least partial relief
of symptoms. The study, however, did not meet critical physicians'
demands scientific proof. Similarly, use of light therapy to cure
certain types of cancer is still awaiting conclusive validation.
Support is also lacking for the theory that coloured 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.
Coloured-light therapies such as syntonic optometry have never been
scientifically verified. Although the coloured beams striking the
eyes are supposed to regulate various body functions by stimulating
corresponding areas of the brain, there is no evidence that this
actually occurs. There is disagreement, too, over exactly how such
therapies might work. When light enters the eye, brightness-and
colour-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 has
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 is clear that exposure to sunlight increases the body's
supply of Vitamin D-a necessary for healthy teeth and bones-critics
say that its benefits stop here.
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.
Side-effects
Overexposure
to ultraviolet rays can cause skin cancer and may contribute to
premature ageing 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. If you are taking light therapy
for skin cancer, you may find that the dye often used in these treatments
increases your sensitivity to sunlight.
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