Eye Disorders One of the most critical components of your eye is the cornea, the window of your eye. The job of the cornea is to bend, or refract, light rays so that they focus on the retina at the back of your eye. Refractive errors occur when the cornea fails to focus light rays precisely on the retina. The perfectly focusing eye is an emmetropic eye.
Light enters the eye and is sharply focused on the retina.
Myopia You may be familiar with the term myopia, also known as near-sightedness. Myopia is the result of an eyeball which is too long, or a cornea which is too curved. In both cases, light rays entering your eye fall short of the retina, and objects in the distance appear blurred. Hyperopia Hyperopia, or far-sightedness, is the opposite of myopia. Here, you eye is too short or your cornea is less curved.