Infections of body tissues, particularly of the eye or of wounds, are treated by brief low-intensity irradiation with ultraviolet radiation in the UVC band. A suitable treatment device contains a light-emitting diode producing UVC radiation at a wavelength of about 265 nm, at a power output of 5 mW, directed on to a zone of tissue about 4 mm in diameter. An optical aiming system indicates the zone of tissue to be irradiated. Irradiation for periods as brief as 1 second has been found effective, which equates to a dose of 4 mJ/cm2 delivered to the tissue. Longer periods and higher intensities may be used for more resistant infections. Such irradiation may be delivered endoscopically to treat internal infections or to prevent infection during surgery. The device may be hand held or mounted to an ophthalmic slit lamp or other support.
