As a child, I didn’t know that things in the distance were not supposed to look blurry. So it never occurred to me to tell my parents that my vision was a problem. When I was about seven years old, my parents finally figured out that I needed glasses when I couldn’t see the boats they were trying to point out to me while we were on vacation in Seattle.

I was far from alone in having poor vision as a child. According to the American Optometric Association (AOA), one in four children have an undetected vision problem. That adds up to 10 million school children in America who have vision conditions that can affect their ability to do well in school. Plus, poor vision can result in headaches, tiredness and eyestrain.

Here is the AOA’s list of 10 clues parents can watch out for that may mean a child has a vision problem. Keep track if a child frequently:

1. Loses his or her place while reading
2. Avoids doing close work
3. Holds reading material closer than what seems normal
4. Tends to rub his or her eyes
5. Has repeated headaches
6. Turns or tilts the head to use only one eye
7. Frequently reverses the order of letters or words when reading or writing
8. Follows along with a finger when reading
9. Skips or confuses small words when reading
10. Consistently performs below potential

Children are not born knowing how to see. Just as their brains need to learn to use their legs to walk, they also need practice using their eyes to see well. Don’t trust a basic vision exam to tell the whole story. Just because a child can see past the big E on the eye chart doesn’t mean everything is okay. If you have any concerns or questions about your child’s vision, schedule an appointment with an optometrist right away.

If you don’t have an optometrist, the AOA’s Web site can help you find an optometrist in your area.