Vision disorders, computer illustration. In normal vision (top) light (red lines) enters the eye through the transparent cornea and passes through the lens (dark blue), focusing on the retina (orange). The retina is continuous with the optic nerve, which transmits visual information to the brain. In short sightedness or myopia (middle), light is focused in front of the retina because the eyeball is too long. In long sightedness or hyperopia (bottom), the focal point is behind the retina because the eyeball is too short. In these disorders the resulting blurred vision can be corrected with appropriate lenses.