Also referred to as phototherapy – treatment with light of different wavelengths (infrared, visible, and ultraviolet light), both natural and artificial. Infrared light is emitted by the Sollux lamp and is used in physiotherapy to heat tissues. Visible light of various wavelengths is used in treatment of depression, in dermatology, and to reduce bilirubin in jaundice of the newborn. UV light is mainly used in photochemical therapy.