Light Therapy


Light therapy (also called phototherapy) uses the power of light to treat physical and emotional illnesses. Because the brain and body use light as an indicator for physical processes, light therapy may also be used to regulate an individual’s biological rhythms. These processes include the production of Vitamin D, the inhibition of melatonin, and the stimulation of serotonin and norepinephrine.

Light therapy is commonly used to treat depression brought on by lack of sunlight (seasonal affective disorder, or SAD). It may also be used to ease the effects of insomnia and jet lag by using light to synchronize circadian rhythms. Additionally, phototherapy may be used to help treat skin diseases and certain types of cancer. Ultraviolet Light, or UV Light, has been used to treat anything from tuberculosis to skin disorders such as eczema and psoriasis.

The History of Light Therapy

Since ancient times, civilizations have used sunlight to cure disease. In the 1870s, scientists discovered that sunlight could kill bacteria and other microorganisms. In the 1880s, hospitals in Europe and South America began using light therapy by calming patients with artificial blue light, and stimulating other patients by applying red light to their eyes and other parts of the body. Dr. Niels R. Finsen of Denmark won a Nobel Prize in 1905 for showing that blue-violet, red, and ultraviolet light rays could cure tuberculosis of the skin, measles, smallpox, and scarlet fever.

In the early 20th century, “sun cure”, or therapeutic sunbathing, became a popular medical treatment for tuberculosis, cholera, viral pneumonia, bronchial asthma, gout, and jaundice. Hospitals began to create “heliotherapy wards”, where patients could receive light therapy.

While the use of light therapy decreased around 1940 with the invention of antibiotics, a doctor named Harry Spider made vital contributions to the field of light therapy through his study of light in optometry, also known as syntonic optometry. Dr. Spider found that flashing colored light into a patient’s eyes could either energize or relax the central nervous system. Through experiments, Dr. Spider discovered that warm colors, such as red, orange, and yellow, excited the nervous system. Cool colors (blue, violet, and green), on the other hand, relaxed the nervous system. More important than these specific findings, Spider’s research showed that light could have a huge impact on an individual’s endocrine and central nervous systems.

While sunlight has long been known for its healing prowess, only recently has light emerged as a type of therapy. In the 1970s and 80s, scientists studying the nature of biological rhythms discovered that the lack of light could negatively affect a person’s physical and mental states. In 1983, Norman Rosenthal showed that regular exposure to full spectrum light (which imitates sunlight) could help alleviate the symptoms of seasonal affective disorder in up to 80% of people. This therapy is also known as bright light therapy (the light is more than twenty times brighter than indoor lighting), and is also used by NASA to help its astronauts maintain regular biological rhythms.

How Light Therapy is Practiced

Light therapy influences the secretion of melatonin (which regulates sleep) and serotonin (which controls moods). Melatonin and serotonin also affect body temperature, blood pressure, blood clotting, pain sensitivity, appetite, digestion, and the immune system.

Neurosensory development is a type of light therapy that uses a strobing colored light to improve vision, ease chronic fatigue, and alleviate menstrual discomfort, thyroid problems, insomnia, and depression. The type of light used is determined through a patient’s medical history, as well as a classification as to whether that patient is a “slow” or “fast” neurological type. Then, via a photron ocular simulator (which uses a special glass and full-spectrum light to administer light), light is shined on the patient at a rate between one and sixty strobes per second. The color of the light is also dependent on the individual patient and their particular needs.

Another type of light therapy commonly used is brief strobic phototherapy. Brief strobic phototherapy is used to treat the emotional aspects of physical illnesses. This light therapy uses light that is unpleasant to the patient to help release memories and thoughts that might otherwise remain below the surface. Brief strobic phototherapy is often used to treat depression, anxiety, panic attacks, obsessive compulsive disorder, addiction, eating disorders, and dissociative identity disorder.

Colorpuncture, developed by German naturopath Peter Mandel in the early 1970s, is a type of light therapy where different light frequencies are placed where needles would go in normal acupuncture. This technique is used to stimulate the immune system and as part of a treatment plan for those with mental disorders and addictions. It may also be used in place of acupuncture if the patient is afraid of needles. 

How Light Therapy Works

Usually, light therapy consists of sitting in front of or lying under a “light box” for between 30 minutes and two hours each morning. Some light boxes simulate natural light, including ones that are able to simulate dawn, while others are extremely bright lights, able to make up for a lack of natural light. Another type of light, full-spectrum, simulates sunlight but without the harmful ultraviolet (UV) rays. Cold light, a low-level laser, focuses a laser beam to treat pain, inflammation, wounds, and stimulate healing. Other types of light include infrared and colored light.

While studies show that light therapy is generally safe, there are still precautions individuals should take when undergoing such therapy. Overexposure to full-spectrum light may cause eye irritation, headaches, insomnia, and agitation. Individuals should avoid too much exposure to UV rays, as the rays may cause skin cancer. Additionally, persons undergoing light therapy should avoid taking Vitamin D, as they are likely already receiving enough Vitamin D from light therapy, and additional doses could be toxic.

Conditions Benefited by Light Therapy

Light therapy may be used to treat the following conditions:


According to a 2006 review by the American Journal of Psychiatry, light therapy is just as effective as drugs in treating seasonal affective disorder. Most patients noticed improvements within a week of beginning treatment.

Sleep Disorders

Light therapy is often used to treat issues related to lack of sleep, including insomnia and jetlag.


Person suffering from dementia often experience trouble sleeping and mood swings. Light therapy may be able to alleviate these symptoms.


  1. Bratman, S. The Alternative Medicine Ratings Guide: an expert panel rates the best treatments for over 80 conditions, Prima Health A Division of Prima Publishing (1998)
  2. Brown, L. Alternative Medicine, NTC/Contemporary Publishing (1999)
  3. Deepak Chopra, M.D. Alternative Medicine: The Definitive Guide, Celestial Arts (2002)
  4. Nancy Allison. The Illustrated Encyclopedia of Body-Mind Disciplines, The Rosen Publishing Group (1999)
  5. Servan-Schreiber, D. The Encyclopedia of New Medicine: Conventional & Alternative Medicine For All Ages, Rodale International Limited (2006)

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