Astigmatism is one of the most common refractive errors in the human eye. It’s estimated that about 40% of adults have some level of astigmatism affecting their vision. Unlike myopia (nearsightedness) or hyperopia (farsightedness), which affect only one’s ability to see things close up or far away, astigmatism causes both near and far vision to suffer, leading to all-around blurred or streaked vision.
In this article, we’ll look at the causes of astigmatism, how astigmatic vision differs from normal vision, and why you should schedule an eye exam if you’re experiencing difficulty seeing things close and far away.
What Is Astigmatism?
For someone with normal vision, the eyeball is very nearly a perfect sphere. With an even curvature around the eye, the eye’s lens is perfectly shaped and placed to project a clear image onto the retina, giving sharp, clear vision at all focal lengths.
With astigmatism, the eye is not round and is shaped more like an egg or a football than a sphere. As a result, the image projected by the lens is focused in front of and/or behind the retina, not on the retina itself.
Because of that, the eye can’t create a clear image of what’s in front of it, and the entire field of vision becomes blurry at any focal length.
What Causes Astigmatism?
There’s no real consensus on what causes astigmatism. Heredity seems to play a part in it, as individuals with a parent or parents with astigmatism are slightly more likely to have or develop the condition. Most cases are congenital, even if they never cause any significant vision problems or only develop into vision problems later in the person’s life.
An injury to the cornea or cataract surgery can also cause astigmatism. Scar tissue on the eye can contract and warp the eyeball, leading to astigmatic vision. Contrary to popular belief, reading in the dark or sitting too close to the TV can’t cause astigmatism (but they can cause eye strain and exacerbate existing refractive errors, so they should be avoided, nonetheless).
What Does the World Look Like With Astigmatism vs. Normal Eyesight?
The main vision issue caused by astigmatism is blurry vision when looking at objects at any distance. Your vision can be blurred when you’re looking at something nearby:
Or, when you’re looking at something far away:
Another common issue caused by astigmatism is a flare or “smearing” of lights, causing lights to appear as bands of color instead of distinct points:
You should schedule an eye exam if you’re experiencing any of these conditions. Your vision problem may be easily corrected using one of several solutions.
How Can Astigmatism be Diagnosed and Corrected?
Your eye doctor will perform some tests to determine whether you have an astigmatism and what can be done to bring your vision into focus. Tests may include:
- Visual Acuity Test: You will be asked to read from an eye chart that’s located a fixed distance away.
- Refraction test: An instrument will allow the eye doctor to measure how light bends as it passes through your eye.
- Keratometry: A special meter will gauge your eye and determine if it is spherical or out of round.
- Phoropter: You will return to the eye chart, and various lenses will be placed in front of your eye. You’ll tell your eye doctor whether each lens improves your vision.
If your optometrist determines that you have an astigmatism, you have several options available to you:
- Eyeglasses are the simplest and usually most affordable form of treatment. Your eyeglass prescription will contain information about the nature of your astigmatism, so your new eyeglasses will correct both your near and distant vision.
- Once reserved only for cases of myopia or hyperopia, contact lenses are available to correct astigmatism. Contacts, while more expensive than glasses, correct a wider field of vision and can make your overall eyesight better than glasses can.
- Surgery options exist for extreme astigmatism or cases where glasses and contacts are undesirable, such as LASEK and other procedures that can effectively correct astigmatic vision.
Regardless of how you choose to have your astigmatism corrected, you should schedule annual eye exams. Over time, the shape of your eye can change, and for most people, vision will worsen with age. By having your eyes checked regularly, you can get up-to-date corrective lenses that keep your vision sharp and provide early warning of the onset of other conditions such as macular degeneration, glaucoma, and cataracts.
The World Doesn’t Have to Be Blurry! Call Eyesight Associates and Schedule a Vision-Restoring Eye Exam Today!
Our eye specialists can bring the world back into focus with eyeglasses, contact lenses, or surgeries to correct myopia, hyperopia, astigmatism, and more. Give us a call to learn more: 478-923-5872.