What does phototherapy mean?
Phototherapy is the medical use of light to prevent or treat a health condition. It is most commonly associated with ultraviolet therapy for skin disorders and with blue-light treatment for neonatal jaundice, in which filtered light helps the body convert bilirubin into forms that can be eliminated more easily. Other applications include psoriasis, eczema, vitiligo, and some seasonal affective disorder protocols. In clinical settings, the wavelength, intensity, duration, and safety of exposure are carefully controlled. The term may refer to treatment with natural sunlight, artificial lamps, or focused beams of visible light. It carries a clinical rather than everyday tone, but it describes a broad family of therapies whose common principle is controlled exposure to therapeutic wavelengths. Phototherapy is not the same as radiotherapy, which uses ionizing radiation rather than light. Its importance lies in demonstrating that light can become a precise medical intervention when its biological effects are understood and properly controlled.
nounMedical treatment involving exposure to therapeutic light, especially ultraviolet or filtered blue light, to treat or manage a disease or condition.
- Treatment of a disease or condition by controlled exposure to therapeutic light, particularly ultraviolet or filtered blue light.
"The hospital began phototherapy for infants with severe neonatal jaundice."
"The hospital began phototherapy for infants with severe neonatal jaundice."
"Her dermatologist recommended narrow-band UVB phototherapy for chronic psoriasis."
The plural is uncommon because phototherapy is often treated as an uncountable therapeutic practice; it is useful when comparing several distinct forms of light treatment.
"Several phototherapies have been studied for seasonal affective disorder."
For newborns with high bilirubin, a blue lamp can become the medicine—no pill required.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does phototherapy come from?
The English word combines the Greek-derived combining form photo-, meaning “light,” with therapy, which comes from Greek therapeia, meaning “service, care, or treatment.” These components also appear independently in English scientific vocabulary, including photosynthesis, photography, and photochemistry. The modern medical sense developed alongside the study of sunlight and artificial ultraviolet radiation as treatments for disease.
Related word forms
How phototherapy is actually used
This is a formal medical term used chiefly in clinical, dermatological, paediatric, and research contexts.
Easily confused with phototherapy
Phototherapy uses therapeutic wavelengths of light, whereas radiotherapy uses high-energy ionizing radiation to damage or destroy cancer cells.