Excimer 308-nm light is a form of targeted phototherapy that delivers a specific wavelength (308 nm) of ultraviolet B (UVB) radiation using an excimer laser or an excimer lamp. Both have shown similar results regarding efficacy, but have technical differences.


Excimer light treatment is a development of whole body narrowband UVB. Narrowband UVB delivers energy at a wavelength between 311–312 nm for the treatment of localized psoriasis and vitiligo. The disadvantages of narrowband UVB include irradiation of the whole body and the need for a high number of treatments.


The UV ray generated by the excimer light is delivered via a hand-held wand that focuses on the lesion. Compared with narrowband UVB, its advantages are:


  • Healthy skin surrounding the affected areas is not exposed to radiation.
  • Different templates are used according to the area to be treated.
  • A higher dose of radiation can be delivered, with a reduced cumulative dose of irradiation.
  • In some cases, a shorter course of treatment is effective.
  • It can be used in areas difficult to reach with conventional phototherapy, such as ears and genitals.
  • It can be used in children, as it is a relatively friendly–looking piece of equipment.