Abstract: Apparatus is disclosed for directing flashes of light into the eyes of a user. LED's 17 are mounted in the eyepieces of goggles 3 or spectacles 43 to face the eyes of a wearer. The goggles 3 or spectacles 43 are opaque and are provided with opaque flanges 9 to avoid ambient light reaching the eyes of a wearer. The frequency and brightness of the flashes is variable. The device is useful in the treatment of migraine, pre-menstrual syndrome, insomnia and nervous tension. Alternatives are disclosed using remote light sources 51 and optic fibres 53 or mirrors 57, mechanical or electro-optic shutters 59, 61, and arrangements using a common light source 51 for both eyes.