Teddy Waskawich, age 11, of Niagara Falls, Ontario, Canada, for his question:

WHAT IS ASTIGMATISM?

Almost everyone has some astigmatism that is caused by abnormalities in the curve of the eye's cornea. The condition makes objects appear blurred, and it happens because rays of light from different parts of the object being viewed do not all focus equally on the retina of the eye.
Astigmatism can give a person both eyestrain and headaches.
The condition of astigmatism can be corrected by eyeglasses or contact lenses. In some extreme cases, correction has been made by corneal transplantation. This is an operation in which the scarred cornea is replaced by clear corneal tissue from another person.
If you have any eye problems, discuss the problem with your family doctor.