What Is It?
Light therapy is the use of natural or artificial light to treat various ailments, but primarily depressive and sleep disorders. It may be administered by a physician, physical therapist, psychiatrist, or psychologist–or done on one’s own with proper instruction from a trained professional. While exposure to the full-spectrum wavelength of natural sunlight is considered the best form of light therapy, it is not always possible for many people to get outdoors. Therefore, light therapists often recommend treatment with simulated sunlight from light boxes.
The form of light therapy most commonly used today is known as bright-light therapy. It requires that you sit near a special light box fitted with high-intensity light bulbs, which may provide either full-spectrum or white light. This type of light therapy has been proven to be particularly useful in treating seasonal affective disorder (SAD), also known as the “winter blues,” a form of depression that occurs as the amount of daylight wanes with the change of seasons. It has also been shown to be effective for some sleep disorders.
For SAD, practitioners usually recommend sitting for 15 to 20 minutes in front of a light box with 10,000 lux capacity (a lux is the international unit of illumination, one lumen per square meter). This light is about 15 times brighter than normal home or office lighting. You can also receive light therapy by installing full-spectrum bulbs in place of incandescent or fluorescent room lighting. This method is less effective for depressive disorders, however, because they tend to respond better to intense rather than dissipated lighting.
Two other types of light therapy are:
Colored-light therapy. This type of light therapy utilizes filtered floodlights or small beams of light to bathe the skin in different shades of color (usually red, but also white, blue, violet, and occasionally other colors), sometimes in flashing patterns. Advocates suggest that different colors of light affect the body by altering production of neurochemicals in the brain. While more research needs to be done in this area to prove the therapy’s effectiveness, some early studies show promise. In a preliminary study in the journal Headache, patients with migraine headaches were treated with goggles that alternately illuminated the right and left (closed) eyes with red light. Of 50 headaches, 49 were helped and 36 were stopped by the treatment. In another preliminary study, red light was emitted onto the knees of 50 patients with osteoarthritis of the knees. Those who received the red light therapy reported that their pain was significantly reduced as compared to the group that had placebo light therapy (in which the same machine was used, but unknown to the patient, no light emitted was from it).
Cold laser therapy. Also known as soft or low-level laser therapy, this type of light therapy focuses a beam of low-intensity laser light at a particular area of the body. The treatment is thought to initiate a series of enzymatic reactions and bioelectric events, which stimulate the natural healing process at the cellular level. Supporters suggest that cold laser therapy is useful for relieving pain, reducing inflammation, and helping to heal wounds, however there has been no scientific proof of this.
How Does It Work?
While some of the claims for the health benefits of light therapy are as yet unproved, it is known that adequate light is vital to many aspects of healthy living. For example, light is needed to maintain the body’s circadian rhythms, or internal clock. These rhythms control numerous functions, from hormone levels to sleep and wake cycles. Studies show that the eye turns light into electrical impulses, which travel along the optical nerve to the brain, triggering the release of the mood-altering chemical, serotonin and other chemical messengers. Healthy levels of serotonin and other neurotransmitters are very much involved in one’s emotional well-being.
Health problems can develop when the circadian rhythms are thrown off. This can occur when people spend much of their time indoors, work odd shifts, or fly across time zones, or when the amount of daylight decreases in the fall and winter. Bright light therapy helps the body restore its natural circadian rhythms.
What You Can Expect
Before you use light therapy for depression or for any other ailment, you should talk to your doctor. (Indeed, if you suffer from any type of depression, you should be under a doctor’s care.) Once you have a professional’s recommendation, you can probably do light therapy at home. For depression, the therapy may be part of a more comprehensive treatment plan that also includes exercise, dietary changes, and medication.
Not surprisingly, the best way to get light therapy is to go outside for about 30 minutes and raise your face to the sky (don’t look directly into the sun, however). Even on a cloudy day, the sun provides the full spectrum of light that the body needs.
When being outdoors is not an available option, the most common way to receive light therapy is to use a light box fitted with a white or full-spectrum light. Many users report that full-spectrum light, which simulates daylight, is more pleasant to the eye than white light, although there is no difference in the benefits received. Many full-spectrum lights now eliminate the skin-damaging ultraviolet (UV) rays.
For a treatment, the light box (which is small enough to be set on a table) should be placed where it is level with the eyes. Follow the manufacturer’s instructions regarding where you should sit for optimum results. You may read, eat, or do other activities during the session. Depending on the brightness of the light source, treatment can take anywhere from 15 minutes to three hours.
If you’d rather move around during your treatment, you may prefer to use a light visor, which is worn on the head like a tennis visor and powered with rechargeable batteries. Because light visors typically have a maximum of just 3,000 lux, but because they are worn so close to the eyes, treatment sessions don’t necessarily take longer.
Bright-light therapy has been used very effectively since the late 1980s to help those suffering from seasonal affective disorder (SAD). Studies show that people with SAD notice significant mood improvement within a week of starting daily morning sessions. Scientists believe that light therapy for SAD works by suppressing daytime elevation of the hormone melatonin (a substance that promotes sleep), and increasing the amount of mood-elevating brain chemical serotonin. Interestingly, these changes in neurotransmitters can reduce carbohydrate cravings and the need for an inordinate amount of sleep–both hallmarks of this form of depression.
Studies also show that bright-light therapy can also be effective for insomnia, helping to restore normal sleep patterns in people who can’t fall asleep at night or who wake up too early in the morning (there are dawn/dusk simulators sold by light box companies for this purpose).
Light therapy has also been used to treat the depression associated with PMS, chronic anxiety and panic attacks, severe jet lag, and eating disorders such as anorexia nervosa and bulimia. A specific form of light therapy with ultraviolet radiation is used by dermatologists for psoriasis. This is only done under a physician’s direct supervision, however.
How To Choose a Practitioner
Light therapy is usually administered (or recommended for home use) by a physician, physical therapist, or psychologist. Look for a well-trained, experienced clinician.
If the therapy is prescribed by a physician, insurers may reimburse for the cost of the lighting systems used to treat seasonal affective disorder and skin problems.
Check with a health-care professional before starting any form of light therapy.
If you have glaucoma, cataracts, or retinal detachment, check with your eye doctor before starting light therapy.
Never look directly into the light source during your therapy.
If you have a rash accompanied by a fever, call your doctor before starting light therapy (you may have an infection such as measles or chicken pox).
If your skin or eyes are highly sensitive to light, avoid light therapy.
Avoid light therapy if you have any type of bipolar disorder.
David Edelberg, MD