Most common eye disorder.
Associated with blurring of vision because visual images are not properly focused on the retina.
Light entering the eye is refracted by the lens and the cornea.
If vision can be corrected with eyeglasses or contact lenses a refractive error is present.
Nearsightedness refers to, myopia, when the focus of the images occurs in front of the retina.
Farsightedness refers to the process of hyperopia, when the focus of the image falls behind the retina.
When the cornea is more elliptical than spherical the images are focused in more than one location impairing vision and is referred to as astigmatism.
As the individual ages the lens stiffens and the lens looses its ability to accommodate, resulting in presbyopia, correctable with reading glasses.
Approximately 25% of the population is nearsighted, 25% is farsighted, and everyone will eventually develop presbyopia.
Correction can be made with eyeglasses, contact lenses or surgery.
Corneal refractory procedures include cutting the cornea to alter its shape, radial keratomy consisting of creating deep radial incisions with a knife.