20/20 Vision

When you walk in to get an eye exam, the Optometrist or Optician checks your vision. The normal value is considered to be 20/20. It tells how clear and how sharp your vision is when looking at an object that is 20 feet away. While there, you will see a chart with objects or more commonly letters. You’ll be asked to read each line. The distance from this chart is supposed to be 20 feet.

What is the meaning of this fraction? Well, the first, or top number, means the distance in feet that you can clearly see a pair of objects. The second, or bottom number, means how clearly you can make out those objects. If the doctor talks about visual acuity, they mean that a person can see a small detail from 20 feet away. In the United States 20/20 is used as the normal values for eyesight.

If the doctor says you have 20/60 vision, he/she is telling you that you can see from 20 feet away what a person with “normal” eyesight would be able to see from 60 feet away. The easiest way to remember that is that if you see an object that is 20 inches in size, at a 20 foot distance, then you are said to have 20/20 vision. The bigger the size the object gets for you to see it, the higher the lower number will go up. As this happens, glasses or contacts are often advised.

Some schools will do annual testing on different grade levels to help see if the child is having a vision problem. Vision can be affected by many things. It can be affected by being dry or dehydrated. Medications can cause changes as can room temperature and allergy problems.