Part of a comprehensive eye exam involves assessing your visual acuity. But what is visual acuity, and how is it measured? Your optometrist explains in this post.
Visual acuity (VA) refers to the clarity of your vision. It is measured by your ability to see the details of letters, symbols and objects from a certain distance. Overall vision comprises various elements such as depth perception, color vision and peripheral vision. Note that only central vision, which refers to the ability to see objects when looking straight ahead, is examined during a VA test. There are no special preparations needed as the test is quite simple.
Your eye doctor will use either Snellen or Random E chart to measure your visual acuity. The Snellen chart contains random letters or symbols arranged into rows and columns. These letters are in varying sizes, with the bottom row usually containing the smallest letters. During the test, your eyes will be covered one at a time. You will then be asked to read the chart using your uncovered eye. The chart should be positioned 14 to 20 feet away.
The Random E chart contains only the letter “E” facing different directions: up, down, left and right. You’ll be asked to identify the orientation of the letter. This test is also used for children who cannot read yet.
VA is quantified using fractions such as 20/20. You often hear the term 20/20 vision, and might even equate it with perfect eyesight. However, this fraction simply indicates that your visual acuity remains normal even when viewing objects 20 feet away. Keep in mind that this fraction varies from person to person. If you have 20/40 vision, it means you have to be 20 feet away to see an object that people with “normal” eyesight can see from 40 feet away. If your visual acuity is impaired, your eye doctor may prescribe corrective eyeglasses or contact lenses to improve your vision.
At NOVA Vision Center, we recognize the importance of eye care. We provide stellar eye-related services and products for all. You may call us at (703) 291-0080. We cater to patients in Alexandria and Arlington, VA.