Astigmatism: Causes, Symptoms, Diagnosis, and Treatment

Astigmatism is a common condition in which your eye isn’t totally round.

Astigmatism occurs in people who have a cornea shaped like a football (i.e., not completely round). The cornea should be shaped round (like a baseball) to reflect light perfectly. When it is shaped like a football, there is more than one curve on the cornea, generally a flat one and a steep one. This makes light reflect on more than one point in the retina, resulting in blurry vision for the patient. Frequent farsightedness and nearsightedness occur with astigmatism.

Astigmatism Symptoms

Here are four of the common symptoms of astigmatism: 

  1. Eyestrain
  2. Blurry or distorted vision
  3. Trouble seeing at night
  4. Headaches

Astigmatism Causes

Most individuals are born with it, but doctors don’t know why. You can also get astigmatism after an eye disease, an eye injury, or surgery.

Rarely, a condition called keratoconus can induce astigmatism by making the front part of your eye (your cornea) more cone-shaped and thinner. You’ll apparently need contacts (but not necessarily glasses) to see clearly.

Contrary to popular belief, you can’t get astigmatism from sitting too close to the TV or reading in low light.

Astigmatism Diagnosis

Phoropter

Visit an eye doctor if you notice some changes in your vision. You’ll need to go for a comprehensive eye exam. Your eye surgeon will examine the sharpness of your eyesight by inviting you to read an eye chart carefully. They’ll also use machines to measure your vision, including:

  • Topographer/keratometer. This tool uses a circle of light to measure the curve of your cornea.
  • Phoropter. You look through a range of lenses to find the ones that give you the most precise vision.
  • Autorefractor. This device shines a light into your eye and measures how it shifts as it bounces off the back. This gives your doctor an idea of what kind of lenses you need.

Surgery-Treatment

Two of the famous surgeries which are utilized to fix astigmatism are astigmatic keratotomy and LASIK. Astigmatic keratotomy is achieved by cutting a microscopic incision in the eye and completely reshaping the cornea from scratch. At the same time, LASIK is performed by cutting a small flap in the eye and then reshaping the cornea through safe lasers. Although these procedures are performed somewhat differently, they are both used to reshape the cornea and produce clearer vision. The surgery objective is to make the cornea more spherical like a basketball instead of shaped like a football.

Glasses repair astigmatism by redirecting the incoming light to the retina. This produces a clearer vision for an individual living with astigmatism. Contacts work similarly also and are used to redirect the light. Many years ago, there were only rigid gas permeable contacts available for people living with astigmatism, but times have changed, and today there are soft lenses available as well. Depending on your eye prescription and how much astigmatism you have, it will affect your correction options. If you think you have astigmatism, or know you do, talk to your eye doctor about the type of correction options available and the ones that would be most useful for your lifestyle and vision.

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