Apparatus is provided including an extraocular device, which includes an eyeglasses frame, which is placed in front of an eye of a subject, and a power source coupled to the eyeglasses frame and configured to emit a beam of light that is outside of 380-750 nm. A light-guiding element is coupled to the eyeglasses frame and at least one optical coupling-in element and at least one optical coupling-out element are optically coupled to the light-guiding element. The coupling-in element is positioned such that the beam of light is directed into the light-guiding element via the coupling-in element, and the coupling-in and coupling-out elements are positioned such that the beam diverges from a focal point located within 3 mm of the coupling-out element. Other applications are also described.
