Astigmatism is a condition in which your eye, especially your cornea or the clear front part of the eyeball, isn’t completely round.
Ideally, an eyeball is shaped like a perfectly round ball, or a marble. Light comes into it and bends evenly, which gives you a clear view. But if your cornea is shaped more like a rugby ball, light is bent more in one direction than another. That means only part of an object is in focus. Things at a distance may look blurry and wavy.
It is common to have astigmatism along with nearsightedness (myopia) or farsightedness (hyperopia). These three conditions are called refractive errors because they involve how your eyes bend (refract) light.
Astigmatism is fairly easy for an optometrist to fix with glasses or contact lenses.
Symptoms of astigmatism may include:
● Blurry or distorted vision
● Eyestrain
● Trouble seeing at night
Causes of Astigmatism
Most people are born with it, but experts don’t know why. You can also get it after an eye injury, an eye disease, or surgery.
Rarely, a condition called keratoconus can cause astigmatism by making the clear front part of your eye (your cornea) thinner and more cone-shaped. You’ll probably need hard contact lenses and not spectacles to see clearly.
You can’t get astigmatism from reading in low light or sitting too close to the TV.
Diagnosis of Astigmatism
Astigmatism symptoms come on slowly. Go to an optometrist if you notice changes in your vision. You’ll need a complete eye exam. Your doctor will test the sharpness of your eyesight by asking you to read an eye chart. They’ll also use tools to measure your vision, including:
● Phoropter. You look through a series of lenses to find the ones that give you the clearest vision.
● Keratometer. This machine measures the bend in the center of your cornea. It finds the steepest and flattest curves. The measurements tell your doctor about the shape of your cornea and how well it can focus.