Astigmatism is a very common vision issue but is often misunderstood. Many of us fall somewhere on the astigmatism spectrum, but we may not recognize a problem at first. It is not an eye disease or an indicator of a health condition but is related to how light is focused within the eye. We’ll clear up what may be behind your blurry vision and share 10 facts you need to know about astigmatism.
What Is Astigmatism?
Astigmatism is a vision condition that affects nearly 1 in 3 Americans. When your cornea has an irregular curvature, light rays coming into the eye are not focused properly, causing objects to appear blurry. You may also sense there’s a problem if you have frequent headaches, your eyes feel tired, or images in the distance are hard to see.
The exact cause of astigmatism has not been pinpointed, but genes most likely play a role. The condition can also appear following a surgical procedure or an eye injury. Astigmatism symptoms and whether the condition worsens differs from person to person, but in general, we all are born with some degree of it.
Other issues affecting your vision can coincide with astigmatism, including farsightedness, called hyperopia, and nearsightedness, known as myopia. Since these eye conditions affect how our eyes refract or bend incoming light, they are known as refractive errors.
Facts About Astigmatism
1. It’s Caused by a Cornea with an Irregular Shape
If you have astigmatism, you may have noticed you have trouble focusing, whether up close or on distant objects. When light enters the eye, the transparent surface called the cornea and lens bend the rays to focus correctly at the back part of the eye, or the retina. The cornea has a smooth surface with an equal curve in each direction. Astigmatism affects the curvature of the cornea so that the surface is curved unevenly, creating a rough layer, and light is then refracted incorrectly.
If you are afflicted with astigmatism, the shape of the cornea is not the more favorable round shape of a basketball but is shaped more like a football. A rounded cornea monitors the light coming in from the world around you, allowing you to focus and clearly see things. Any differentiation from this shape causes the light to distribute unevenly, making objects a blur.
2. Astigmatism Is Divided into Two Categories
There are two kinds of astigmatism, lenticular and corneal. If your lens curve irregularly, it is called lenticular astigmatism. If your cornea curves differently in one direction, it is known as corneal astigmatism.
3. There Are Three Types of Astigmatism
Astigmatism is further divided into three different types.
- Myopic astigmatism is when one or both eye meridians, the invisible lines that divide your eye from left to right, bottom to top, are nearsighted.
- Hyperopic astigmatism results when one or both meridians are farsighted.
- Mixed astigmatism occurs when you have one nearsighted meridian and one farsighted meridian.
Astigmatism can also be categorized as regular or irregular astigmatism. Regular astigmatism occurs when the principal meridians are perpendicular to each other, and irregular astigmatism occurs when the principal meridians are not 90 degrees apart. Irregular astigmatism can be caused by cornea scarring, eye surgery, or keratoconus, a disease that thins the cornea.
4. Most of Us Have Some Degree of Astigmatism
Nearly all of us are born with some form of astigmatism, but many times it doesn’t affect our vision to the point of concern. You may go several years without spotting any issues until your vision starts to change as the condition worsens. Astigmatism can affect anyone, but studies have shown that Hispanic, East Asian, and Bangladeshi groups have a higher prevalence of astigmatism. Also, if you already require glasses or contact lenses, you have a 40% chance of having astigmatism too.
5. Symptoms of Astigmatism Can Be Missed
Vision problems can come on very slowly, so you may miss the first tell-tale sign of astigmatism. Headaches and eye strain can also be tied to other conditions, so diagnosis may be delayed. The most proactive approach to identifying astigmatism or other eye issues is to visit your eye doctor on a regular basis.
Many everyday tasks can also cause vision problems, like frequent use of electronics, smartphones, and computers. Keeping up with regular eye check-ups can help detect a vision issue early before it becomes a problem.
6. Look Out for Early Signs to Avoid Future Issues
While astigmatism is not dangerous, if it continues to progress without treatment, it can lead to other eye issues that are more permanent and disruptive. Lazy eye, for instance, can be caused by astigmatism that was present at birth. Taking your children for regular eye exams is a good way to keep tabs on their eye health and make sure their eyesight is in top shape.
7. Astigmatism Can Affect Depth Perception
Viewing the world around you in 3D refers to your depth perception. Astigmatism, among other eye issues, alters your depth perception so you may not be able to determine the correct distances between objects and how close or far they are from you.
Most people may only notice an issue with depth perception if they have astigmatism in one eye, which causes their sight to be off balance. Borders of objects may also be blurred and out of focus.
8. Your Optometrist Can Help Diagnosis the Condition
If you start to notice your vision is blurry or have difficulty seeing things up close or from a distance, your eye doctor can help determine the cause with an eye examination. This exam will include reading the letter chart and measuring your visual acuity, which is how well your eyes can see shapes and finer details. Your optometrist will also measure how well your eyes can focus using several lenses in front of your eyes. He or she will then analyze your results to help diagnose astigmatism or other vision conditions.
9. Your Condition May Progress with Time
While astigmatism is not an eye disease and does not negatively affect your eye health, a deterioration in vision can still affect your life. Without proper corrective lenses or treatment, you may notice your astigmatism becoming worse as the years go by, and things you could once see well, are no longer in focus. If you keep up with your eye care and regular eye exams, your doctor may spot these changes, even if they’re minor, and can get ahead of further issues.
10. Astigmatisms May Run in the Family
You can thank your parents for your astigmatism. The odd-shaped cornea associated with astigmatism is thought to be a genetic trait and may be passed from one generation to the next. Your doctor will likely discuss your family history with you since having relatives with the condition increases your risk of developing it.
Astigmatism Treatment Options
A routine eye exam includes tests that look for farsightedness, nearsightedness, and astigmatism. One such test is called retinoscopy and it involves a variety of lenses being placed in front of your view while your optometrist shines a light into your eye. This helps determine the amount of astigmatism and what treatment is best for you.
Most of the time, prescription contact lenses or glasses can change how the eye takes in light to correct the astigmatism. Your doctor may also suggest orthokeratology, which is a noninvasive procedure that reshapes the cornea curvature slowly over time. Using a series of special contact lenses, the cornea is smoothed and evened out to fix the astigmatism.
Laser surgery can also treat some types of astigmatism. The cornea shape is altered using a laser that takes away a portion of the eye tissue. For instance, LASIK, the most common type of refractive surgery, improves your vision by rounding out the cornea permanently to eliminate the astigmatism.
If you’re ready for the world to come into focus and correct astigmatism, schedule an eye exam today.