why do people have to wear glasses

Have you ever had an? If so, your doctor has probably asked you to cover one
and read letters from a special chart. charts usually contain several rows of. The top begins with very large letters. The letters get smaller and smaller the closer the rows are to the bottom of the chart. What does identifying your have to do with eyeglasses? Each of the chart has been assigned a number. During the, patients read each of the chart until the letters become too small to read easily. If you can read the labeled 20 from a distance of 20 feet, this means you have 20/20. 20/20 is considered normal. If you can only the giant letter at the top of the chart labeled 20/200, you have 20/200.

A score of 20/200 means you would need to stand much, much closer (20 feet) to read something people with normal can read from 200 feet away. People with scores of 20/200 or worse are considered. There are many different medical reasons people wear glasses, but the simple answer is that glasses help people better. Some people wear glasses for reading things that are far away or for driving. Other people only wear glasses when they're doing an up-close activity, like reading, writing, or. Some people wear glasses all the time. People who have difficulty seeing objects that are far away are called Б " or Б. " This means they can easily objects that are close to them, but when viewing objects in the distance, the image can appear.

Nearsightedness occurs when the physical length of the is longer than the length, meaning the visual image is focused in front of the, rather than directly on it. People who have difficulty reading and seeing things close-up are called Б " or Бfar-sighted. " Farsightedness occurs when the visual image is focused behind the, and may be caused by weak focusing power or the being too small. Another condition that can cause people to need glasses is "," which occurs when part of the is irregularly shaped. Thankfully, myopia, hyperopia, and can usually be corrected by wearing eyeglasses or contact.

Both eyeglasses and use or to bend the light entering the. This refocuses the, helping to correct problems. Children need to wear glasses for different reasons. The reason your child needs to wear glasses is checked below: Myopia (my-OH-pee-ah) ( near-sighted ) - Your child can clearly see objects that are close, but needs glasses to clearly see objects that are far away. Normally, a child will not outgrow being near-sighted. In fact, stronger glasses may be needed until the child is 12 to 14 years of age or possibly longer. Hyperopia (hi-per-OH-pee-ah) ( far-sighted ) - Hyperopia is normal in children and does not require glasses. However, if the hyperopia is severe, your child s eyes will have to work harder than normal to focus on close objects.

Accommodative Esotropia (ah-COM-mo-DAY-tive ES-oh-TROE-pee-ah) - Your child has excessive hyperopia which causes his or her eyes to cross. Wearing glasses will control the crossed eyes. Astigmatism (ah-STIG-mah-tiz-um) - Your child s cornea (front part of the eye) is oval-shaped rather than round. This causes blurred vision which can be corrected with glasses. Anisometropia (an-eyes-oh-meh-TROE-pee-ah) - The two eyes are different which may cause poor vision in one eye. Glasses help by individually correcting for this difference. Note: It is important your child wears glasses as directed by the doctor (Picture 1).

It will not harm your child s vision to wear glasses longer. If your child plays sports, he or she should wear a sport strap for added protection. You can buy sport straps for glasses where you have the glasses made. The need for glasses or the strength of the glasses may change as the child grows. Being far-sighted is normal for a child and usually does not require glasses. As the child grows, the shape of the child s eyes may change. Yearly eye exams are very important. If you have any questions, be sure to ask your doctor or nurse. HH-I-144 3/91, Revised 5/10 Copyright 1991- 2010, Nationwide Children s Hospital