What is Astigmatism?
Most of us have at least some flaw in our eyesight. If you’re over 40, your close vision is probably in need of reading glasses. That’s presbyopia and is almost universal for people over age 40. If you’re nearsighted, called myopia, that means you can see up close fine, but distance vision usually needs correction. If you’re farsighted, called hyperopia, you can see at distance just fine, but the close vision is blurry.
And then there’s astigmatism. This condition can be misunderstood as to just what it means. Even the name — astigmatism — is often thought to mean “You have a stigmatism.” No, it’s a single word.
Since we deal with all of these issues all the time at Central Valley Eye Medical Group, let’s take this blog to explain astigmatism a little better.
What is astigmatism?
When a person has astigmatism, their cornea is shaped like a football rather than round. Pretty much everyone has this to some degree; it just may not be the noticeable or impacting vision. A normal eyeball is shaped like a perfectly round ball. Light comes into it and bends evenly, thanks to the perfect roundness, making for clear vision.
But when you have astigmatism, the football shape of your eyeball means that the light gets bent more in one direction than another. That means only part of an object is in focus. It often affects objects at distance, and they may appear blurry and wavy.
What causes astigmatism?
Most people are born with astigmatism. No one knows exactly why. It can also develop after an eye injury, eye disease, or surgery. There is a wives’ tale out there that you can develop astigmatism if you read in bad light or sit too close to the TV, but that’s not true.
How do we treat astigmatism?
Not too long ago, the only way to correct for astigmatism was glasses. Contact lenses had trouble adapting to the shape of the cornea. But today’s contact lenses handle it just fine. Usually, contact lenses will have a line at the top, so the patient can align them properly to get the right fit on the eyeball. These are called toric lenses, and they bend light more in one direction than in the other, hence the need to have them specifically placed on the eyeball.
LASIK surgery can now also fix astigmatism by changing the shape of the cornea.