Refractive problems: myopia, hypermetropia, astigmatism
These are the most common eye disorders. They are known as refractive problems (myopia, hypermetropia and astigmatism), since they are related to the way in which the light impacts (refracts) on the retina. Refractive problems are normally caused by alterations on the surface of the cornea which cause the vision to focus in front of or behind the retina, and not directly on it.
