Illinois Eye Center

Understanding Refractive Errors

The “term” refractive error” may sound like a pretty technical phrase to refer to an eye condition. But in fact, it’s one of the most common eye conditions, affecting about 150 million people in the U.S. alone. 

You may even be familiar with some of the most common types of refractive errors, such as nearsightedness and farsightedness. 

Whether you have a refractive error or have questions about your vision, keep reading to learn more about refractive errors and what you can do to find out if you may be affected by one. 

What is a refractive error?

A refractive error happens because the eye isn’t shaped normally. As a result, light doesn’t quite bend the way it’s supposed to when it enters the eye. 

We see things when light hits the retina, tissue at the back of the eye that sends signals to the brain. In people with refractive errors, the light doesn’t hit the retina correctly, often causing blurriness or other vision changes.

What causes refractive errors?

Many things can cause refractive errors. These include aging as well as genetics (passing refractive errors down to a child, for example).

What are the most common types of refractive errors?

There are four main types of refractive errors: nearsightedness (myopia), farsightedness (hyperopia), astigmatism, and presbyopia.

Nearsightedness

Nearsightedness means that things up close are relatively clear and easy to see, while things far away appear blurry. This occurs because images created by light are focused in front of the retina, as opposed to directly on it. 

People with nearsighted vision are usually diagnosed in childhood or adolescence.  

Farsightedness

Conversely, farsightedness means things close up appear blurry, but things far away appear normal. Children, for example, are usually born farsighted and can only see things close to them. They do, however, eventually develop out of it. Some kids may still have some degree of farsightedness, though nearsightedness is by far the most common of the two.

For people with severe cases, nearly everything they see could be blurry.

Astigmatism

Astigmatism occurs when the cornea (a thin tissue that covers the eye) is curved differently than normal. The change in curvature affects how light enters the eye, which makes it harder to focus. Living with astigmatism is sometimes compared to looking at a funhouse mirror; things appear distorted in your vision.  

Presbyopia

Presbyopia is a condition caused by an aging eye lens. As we age, our eye lenses can harden and become less flexible, making it harder to focus light. People often don’t notice anything until their mid-40s, though it can happen earlier. 

How do I know if I have a refractive error?

While refractive errors aren’t preventable, they are highly treatable. Specifically, a routine eye exam is a perfect way to diagnose and manage a refractive error. Your eye care professional can prescribe optimal ways to treat your refractive error, including eyeglasses. 

If you have questions about your eye health, contact the eye care professionals at Illinois Eye Center today! 

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