What is Light Therapy?
Light therapy, which is also known as phototherapy, is a natural healing regime used to treat a variety of disorders which manifest in both the body and in the mind. Light therapy (phototherapy, heliotherapy) is the use of exposure to wavelengths of light which are specific to the therapy. This can include such sources as daylight, lasers, polychromatic polarized light, fluorescent lamps, light-emitting diodes (LED), full-spectrum light, and dichroic lamps. The light is used under controlled conditions, as a prescription. Light therapy is now commonly used for a variety of conditions, including psoriasis and other skin disorders, including epidermal conditions like jaundice in babies, eczema, acne, etc., sleep disorders, such as circadian rhythm disorder, and psychological issues, which includes the treatment of seasonal affective disorder (SAD).1
Body Conditions Treated
For skin disorders, patients may be treated with the help of targeted phototherapy so that UV ray exposure does not lead to skin cancer. Non-targeted phototherapy would be the light which is emitted from sunlight. The advantage of targeted light therapy is that higher dosages of light can be given, since the whole body is not put at risk, allowing skin conditions to be treated quickly and more efficiently. With psoriasis, for example, UV radiation can reduce inflammatory response by suppressing the immune system.
Neonatal jaundice is another condition that benefits from light therapy. It is often as simple as having the parent regularly seat their baby near a window for a prescribed amount of time or through the use of a “bili light” to allow bilirubin in the infant’s body to be excreted. Most cases of jaundice in infants are very easily treated primarily through the use of light therapy.
With any light treatment, patients need to protect their eyes from phototoxicity.2 Long term UV exposure can contribute to cataracts and skin problems. This is why, in non-therapeutic settings, patients should regularly apply sunblock when spending an extended period of time outside to minimize the risk of developing skin problems, and they should always wear sunglasses in order to protect their eyes.
Tanning beds are not at all the same thing as light box therapy. Tanning beds are used purely for aesthetic purposes and are much more dangerous. Ironically, UV light therapy may help treat some kinds of skin cancer, via “ultraviolet blood irradiation”. The FDA has approved this type of therapy for the treatment of T-cell lymphoma. Photopheresis can also be used for transplant rejection. Trials are underway to see if this therapy is also beneficial for rheumatoid arthritis, lupus, Type 1 diabetes, multiple sclerosis, and systemic sclerosis.3
Treating the Mind with Light Therapy
Light therapy can also treat disorders of the mind, such as seasonal affective disorder, major depression, postpartum depression, and bipolar disorder. In the case of SAD, full sunlight may be unavailable, such as in cases where the patient lives in a geographical location where clouds block sunlight majority of the time. Therefore, special light boxes are used to deliver light to patients in these areas where the UV has been largely filtered out (UV light can cause skin and eye damage).
Phototherapy may reset the internal clock of the body.
This can help people who struggle with the effects of sleep disorders, too, such as circadian rhythm sleep disorder (CRSD). CRSD can be chronic or situational, with the latter including situations like the onset of jet lag and the required unusual sleep cycle of shift workers. In treating CRSD or delayed sleep phase disorder (DSPD), it is critical to time the light exposure correctly. The body produces the naturally-occurring, sleep-regulating hormone, melatonin, during times of darkness, not light. Lightboxes can manipulate melatonin production.
It is important to make sure that patients use the lights exactly as prescribed. Phototherapy alters the mood, and too much exposure can trigger anxiety and mania. Patients should not take St. John’s Wort while using light therapy, as that herb is photosensitizing. There are also certain other herbs and medications (i.e., methotrexate, chloroquine) that are contraindicated with phototherapy. Patients should consult with their doctor about any kinds of medications or supplements they take and how they might interact with light therapy.4
A benefit of bright light therapy for depression, though, includes the ability to enhance or avoid medications. For example, pregnant and breastfeeding patients may prefer phototherapy over the use of prescriptions. The type of light therapy for psychological conditions does not contain the UV light used to treat skin conditions. Still, there are other side effects possible, such as headaches, nausea, irritability, eyestrain, and agitation. Euphoria would be a particular concern in bipolar disorder. It is also important to remember that tanning beds are not an alternative to light therapy. Tanning beds increase skin cancer and skin damage risks.5
1, 2, 4 en.wikipedia.org