the use of light to treat medical conditions, especially skin problems or mental health problems

Phototherapy is one of the oldest treatments for psoriasis. 光照治疗是针对牛皮癣的最古老的疗法之一。

Phototherapy is best known for its effects on seasonal depression but can also be effective in other types of depression. 光照治疗对治疗季节性抑郁症的效果最为人知，但是对其他类型抑郁症也可能有效。