Astigmatism is a condition of the eye where light rays are
not focused on a single point on the retina. The result is blurred vision which may be noticed at both far and near
distances. (Although very often, one distance may be more effected than the other.) The reason for the blur
is usually due to the shape of the front surface of the eye (the cornea) deviating from a round (sphere) shape. One
commonly used analogy is to say the cornea is shaped more like a football than a basketball. The point being
that the front of the eye is not round enough (or uniformly spheroidal) to bend the light rays and focus them all at one point.
In reality, astigmatism is often created by mishapen eye parts other than the cornea (e.g. the lens), or in
many cases, is a combination of both cornea and lens shape deviations.
The bottom line is astigmatism is not a disease, rather it is a common condition of the eye, like near-sightedness
or far-sightedness, and it is easily corrected with glasses and sometimes contact lenses. Smaller amounts are being
treated quite satisfactorily with refractive surgery such as LASIK.
Quick facts on astigmatism:
Astigmatism can occur at anytime, to anyone without any known cause. ( I often like to
point out to my patients- that asking why astigmatism occurs is like asking why one ear is higher than the other, or why one
foot is larger than the other. It is a size/shape/symmetry issue. Our bodies are not perfect - although some may
seem more perfect than others.)
Astigmatism is relatively unpredictable, although it can run in some families (i.e. It can have a genetic
component, but doesn't have to.).
Smaller amounts of astigmatism can change very rapidly. (Some people will have short-term astigmatism,
of amounts so small, that they will never know they have it before it goes away.)
Astigmatism is very common- a majority of people who wear glasses have it to some degree.
