0 the use of light to treat medical conditions, especially skin problems or mental health problems:
Phototherapy is one of the oldest treatments for psoriasis.
Phototherapy is best known for its effects on seasonal depression but can also be effective in other types of depression.
Another option is phototherapy, in which the skin is exposed to ultraviolet light.
Phototherapy is very safe, but it can have temporary side effects, including a skin rash and loose bowel movements.
Jaundice usually doesn't require treatment, but some babies need phototherapy.
