What are refractive errors?

Refractive errors are a type of vision problem that makes it hard to see clearly. They happen when the shape of your eye keeps light from focusing correctly on your retina (a light-sensitive layer of tissue in the back of your eye).

Refractive errors are the most common type of vision problem. More than 150 million Americans have a refractive error — but many don’t know that they could be seeing better. That’s why eye exams are so important.

If you have a refractive error, your eye doctor can prescribe eyeglasses or contact lenses to help you see clearly.

What are the types of refractive errors?

There are 4 common types of refractive errors:

• Nearsightedness (myopia) makes far-away objects look blurry
• Farsightedness (hyperopia) makes nearby objects look blurry
• Astigmatism can make far-away and nearby objects look blurry or distorted
• Presbyopia makes it hard for middle-aged and older adults to see things up close 

What are the symptoms of refractive errors?

The most common symptom is blurry vision. Other symptoms include:

• Double vision
• Hazy vision
• Seeing a glare or halo around bright lights
• Squinting
• Headaches
• Eye strain (when your eyes feel tired or sore)
• Trouble focusing when reading or looking at a computer

Some people may not notice the symptoms of refractive errors. It’s important to get eye exams regularly — so your eye doctor can make sure you’re seeing as clearly as possible.

If you wear glasses or contact lenses and still have these symptoms, you might need a new prescription. Talk to your eye doctor and get an eye exam if you are having trouble with your vision.

What causes refractive errors?

Refractive errors can be caused by:

• Eyeball length (when the eyeball grows too long or too short)
• Problems with the shape of the cornea (the clear outer layer of the eye)
• Aging of the lens (an inner part of the eye that is normally clear and helps the eye focus)