Long-sightedness (hypermetropia) occurs when light is focused behind the retina rather than on it, and the eye has to make a compensating effort to re-focus. This can cause discomfort, headaches or problems with near vision. Spectacles may need to be worn all the time or just for close work, such as reading, writing or computer use. In older people, as re-focusing becomes more difficult, distance vision may also become blurred.