DEAR DOCTOR K: At my last visit, my eye doctor told me I have astigmatism. He told me what that means, but I still don't really understand what it is. Please explain it to me.
DEAR READER: Astigmatism means that the eye's cornea has an irregular shape, which causes vision problems. Astigmatism is very common; I am among the several billion people who have it. Fortunately, it's easy to correct.