Phototherapy: A critical review

Phototherapy is defined as the exposure of small, well-defined anatomical areas to non-ionizing radiations using dichromic lamps, fluorescent lamps, light-emitting diodes, lasers, polychromatic polarized light, or very bright, full-spectrum light for therapeutic use. It includes laser therapy, photodynamic therapy, photothermolysis, and visible light under precise control. More specifically, visible light phototherapy utilizes light of a specific wavelength free of ultraviolet light within the wavelengths ranging 415 to 660 nm. In the past, phototherapy was employed mainly for skin diseases and disorders. The recent developments in the technology demonstrated its applications in various ailments alone or combination with other therapy. Several reports showing the effectiveness of phototherapy for conditions such as mood and sleep disorders, cancer, pre-cancerous conditions, and currently investigations are underway in diabetic retinopathy and hair loss. Depending on the medical conditions and the necessity, different types of phototherapies are used for particular ailment with variations in light intensity and exposure time. The standardization of dosage regimen with respect to light intensity and time of exposure, and quality control is indispensable to avoid impending hazards such as photo damage and skin carcinogenesis. However, the development of improved phototherapeutic modalities and new indications has emerged as integral therapeutic component. The purpose of this chapter is to compile all the minute details of phototherapy, including its limitations and safety concerns for providing sensitive and real-time insight.