Refractive Errors

Refractive errors - "nearsightedness" (myopia), "farsightedness" (hyperopia) and astigmatism - are not eye diseases. They are simply anatomical variations in the curvature of the cornea and the length of the eyeball, which affect the eye's ability to focus light.

Myopia

In the nearsighted eye, either the cornea is curved too steeply, and/or the eyeball is longer than average. The net result is that light is brought to focus in front of the retina, resulting in blurred vision.

Hyperopia

In the farsighted eye, the cornea is too flat, and/or the eye is too short, causing light to be focussed behind the retina.

Astigmatism

In an eye with astigmatism, the cornea is curved more steeply in one direction than the other, resulting in two separate images focussed within the eye.

With modern laser technology, the curvature of the cornea can be altered with great precision, allowing the light to be focussed directly on the retina. This is the essence of refractive surgery - LASIK and PRK.