Objective: To assess the therapeutic affect of light on various diseases and disorders.
The importance of light for health and vitality was perhaps more obvious in ancient times than it is today. People living close to nature have an immediate appreciation of the sun, perhaps even worship it religiously, in a way that is lost when one is insulated from nature by many layers of technology. Even a hundred years ago, the medical value of sunlight was still well appreciated. Wounds were known to heal more quickly and with less scarring when sunlight was used as a disinfectant. Tuberculosis clinics flourished in the high mountains of Switzerland. Rickets responded to sunlight. However, sitting around in the sunlight takes time and seems boring in today’s busy world, so the discovery of antibiotics in the middle of this century pushed aside most of these slow but natural cures. When light enters the eyes and strikes the retina, the resultant nerve signals pass not only to the visual cortex of the brain, so we can see objects, but also, over separate nerve pathways, to other brain structures including the hypothalamus, the pineal and pituitary systems, and the limbic system, causing hormonal and emotional effects.
Light therapy techniques range from the most simple and traditional to the most high-tech and sophisticated forms of light-assisted psychotherapy. These therapies may be categorized by the form of light used:
All these forms of light are applied to the eyes or experienced with the eyes. There are yet other forms of light therapy that involve shining light on other parts of the body, for example, direct light treatment of skin conditions or cancer tumors.
Taking a pill is sometimes cheaper and more convenient than staying at a sanitarium. The modern rediscovery of light therapy occurred in a more psychological context. Season Affective Disorder (SAD), also known as winter depression, was identified as a light deficiency problem, which could be corrected with exposure to bright light, especially on awakening in the morning. Of all the forms of light therapy, bright light treatment for SAD is by far the most thoroughly researched and the most accepted by mainstream medicine. “Light boxes”, sources of bright artificial light can be used for SAD sufferers to sit by during breakfast. There is even a battery-operated light “visor”, worn on the head, to shine light directly into the eyes while allowing the wearer to move about. The ultimate high-tech natural treatment is a light “alarm clock”, a dawn simulator, which turns on a gradually brightening light source, starting an hour or two before rising time and reaching its maximum when the (indoor) sun rises! Once the day is started, there is still the problem of inadequate and artificial indoor lighting in the workplace. Conventional fluorescent lamps emit light, which is deficient in many of the colors and wavelengths of natural sunlight. Replacing these lamps with full-spectrum fluorescent’s, more closely imitating sunlight can improve the performance.
If bright light can have such an effect on the brain, mind, and body, it is to be expected that pulsed light would have even more effect. Pulsed light certainly grabs one’s attention; neurologically speaking, neurons tend to report only changing stimuli, quickly tiring of anything steady. So pulsed light might be considered more aggressive form of light therapy, for more severe conditions. This is known as phonic stimulation. Pulsed light is shone into the eyes either from a mask or goggles worn by the patient or by having the patient sit in front of a larger pulsed light source one or two feet away. Typically, the treatment is applied for 15 or 20 minutes per day.