Astigmatism is a common refractive error which is correctable through the use of
eyeglasses, contact lenses or surgery.

If we think of the normal cornea as being essentially spherical in shape, when light
enters the eye, it is refracted or “bent” evenly in all directions, resulting in a sharp point
of focus on the retina. However, if astigmatism is present the cornea is shaped more like
a football or the back of a spoon. So when light enters the eye it is refracted more in one
direction than the other, resulting in blurred vision in at least one of the two principal
meridians.

Astigmatism can be hereditary and is often present at birth. It can also result from
pressure from the eyelids on the cornea, incorrect posture or an increased use of the eyes
for close work. Untreated it can cause headaches, fatigue, eyestrain and blurred vision
at all distances. Astigmatism can almost always be corrected with properly prescribed
eyeglasses or contact lenses. In cases with only a small amount of astigmatism, corrective
lenses may not be needed at all, as long as other conditions such as myopia or hyperopia
are not present. If the astigmatism is moderate to high, however, corrective lenses are
probably needed.