Light therapy or phototherapy consists of exposure to daylight or to specific wavelengths of light using lasers, light-emitting diodes, fluorescent lamps, dichroic lamps or very bright, full-spectrum light, usually controlled with various devices. The light is administered for a prescribed amount of time and, in some cases, at a specific time of day.
Common use of the term is associated with the treatment of skin disorders (chiefly psoriasis), sleep disorder and some psychiatric disorders. Light therapy directed at the skin is also used to treat acne vulgaris, eczema and neonatal jaundice. Light therapy which strikes the retina of the eyes is used to treat circadian rhythm disorders such as delayed sleep phase syndrome and can also be used to treat seasonal affective disorder, with some support for its use also with non-seasonal psychiatric disorders.
Other medical applications of light therapy also include pain management, accelerated wound healing, hair growth, improvement in blood properties and blood circulation, and sinus-related diseases and disorders. Many of these use low level laser therapy and red light therapy in the 620–660 nm range.
