How The Eye Works? A refractive error means that the eye does not bend light (refract) correctly, resulting in the formation of a blurred image on the retina.

Myopia or Near Sighted Eye

If you are nearsighted, the cornea of your eye is overly curved and / or your eyeball is too long. This combination brings images of distant objects (street signs) to a focus point in front of the retina. When the light reaches the retina, a blurred image is seen since the light rays spread apart after the focus point.





Hypermetropia or Far Sighted Eye

If you are farsighted, the cornea of your eye is not curved enough and / or your eyeball is too short. This combination of factors causes the focus point of the eye to be located behind the retina. When light reaches the retina, a blurred image is seen since the light rays have not been brought to focus prior to reaching the retina.




Astigmatism

If you have astigmatism, the cornea of your eye has a non-spherical shape and does not bring light to focus at a single point. Instead, it focuses images over a range of points producing a blurred image. Both nearsighted and farsighted eyes can also have astigmatism.





Presbyopia

Presbyopia commonly occurs after age 40, when the lens of the eye becomes more rigid and does not flex as easily. The result is that it is more difficult to read at close range. This normal aging process of the lens can also be combined with myopia, hyperopia or astigmatism.