What is Astigmatism?
It’s one of the most common visual afflictions in the world.
Do you have it, and if so, what can you do about it?
In the simplest terms, astigmatism refers to a misshapen eyeball. Instead of looking like a baseball, the eye looks more like a football.
The misshaping occurs in the cornea, which is the curved window that covers the colorful part of your eye (the iris).
The cornea’s job is to filter light to one focused point in the back of your eyeball. But when the cornea isn’t perfectly round, light is sent to several points instead of just one.
To your eye, it’s like looking at a cracked mirror: many splintered images instead of one focused picture.
The result is blurred vision, and which can lead to headaches and discomfort. Fortunately, there are many treatments available to help people with astigmatism.
What Causes Astigmatism?
Most people with astigmatism are born with it. In other cases, scratches or injuries on the eye can cause it.
If you have astigmatism, you’re not alone. It’s extremely common. In fact, it’s the most common refractive error in the world.
In a recent study of American children aged 5-17 years old, more than 28 percent has astigmatism of 1.0 diopter or greater. Another study found that over 47 percent of eyeglass wearers in the UK have astigmatism of .075 or greater.
Do I Have Astigmatism?
There’s a good chance you have it to some degree, especially if you also have myopia (nearsightedness) or presbyopia (farsightedness).
If you’ve been having trouble focusing your vision, or if you’ve been having unexplained headaches, you might have astigmatism. To find out for sure, you’ll need to visit an eye doctor. She can determine if you have astigmatism by performing one of the following tests:
Visual acuity - This is a standard test when you read the black letters on the white background. Your visual acuity is represented by a fraction, 20/20 being the standard one. If you have 20/80 vision, for example, that would mean that you would have to stand 20 feet away from something that you *should* be able to see clearly from 80 feet away.
Karatometry/topagraphy - This device shines a light on the cornea, which allows your optometrist to measure the exact curve of your cornea.
Refraction - This refers to how the eye focuses to perceive sight. To measure this, your optometrist will use a phoropter - the big mask-like object that cycles through different types of lenses to determine which one best matches your eyesight - and ask you which lens allows you to see the clearest.
How Can I Treat Astigmatism?
Special contacts, like Toric contact lenses - Offer a wider field of view compared to glasses. They stay rigid, so they correct the astigmatism of the eyeball.
Glasses - This is a common solution for people with astigmatism. A unique cylindrical lens helps the eye compensate for astigmatism.
Orthokeratology - Unlike the toric lenses that you wear throughout the day, the process of orthokeratology, or ortho-K, is slightly different. With this one, you wear specialized lenses for just a small portion of the day - overnight, for example. Habitual use of this can help improve vision during the day, so if you wear the contacts overnight, you’ll be able to see better the following day. This is best for those with a mild astigmatism.
Procedures - You can also get LASIK (laser in situ keratomileusis) or PRK (photorefractive keratectomy) to correct an astigmatism. Both of them involve removing tissues from your cornea in order to reshape it.
Your eye doctor can advise you on the best solution for your specific condition.