If you have great eyesight, you might expect to see 20/20 on your vision chart. Excellent vision is about much more than being able to read up close or see long distances, though. Learn what 20/20 vision really means and whether it's possible to have perfect vision.
WHAT A VISUAL ACUITY TEST MEASURES
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When you go to your optometrist or ophthalmologist for an eye exam, you can expect to take a series of tests. From visual field tests to refraction tests to color vision tests, eye doctors have several ways to assess your vision.
A Snellen visual acuity test reveals how clearly you can see. In doing so, it assesses how accurately your lens and cornea focus light, how sensitive your retinal nerves are, and how well your brain interprets the data it receives from your eyes.
HOW HEALTH CARE PROFESSIONALS MEASURE VISUAL ACUITY
During a visual acuity test, you'll sit 20 feet away from a chart lined with letters of the alphabet. Your eye doctor will ask you to read select rows of letters out loud, and you'll notice that the letters appear smaller with each consecutive row. You'll cover one eye at a time to measure the sharpness of each eye separately.
Sometimes the visual acuity test includes a second step to assess your near vision. For this test, your eye doctor will ask you to read a series of letters off a chart positioned 14 feet away from you. You'll typically remove your glasses or contacts for both parts of the test.
WHAT 20/20 VISION REALLY MEANS
When you receive your visual acuity test results, you'll notice that they appear as a fraction. The number on top is the number of feet that separated you from the chart, which is almost always 20.
The number on the bottom is a little more complicated. It refers to how far away a person with good eyesight would need to stand in order to read the last line that you read correctly.
When it comes to visual acuity test results, 20/20 vision is considered normal. In contrast, 20/60 vision means that a person with normal vision could read at 60 feet what you read at 20.
If you have particularly sharp vision, you can achieve a score that's even better than 20/20. In fact, you might have 20/15, 20/12, or even 20/10 vision.
PERFECT VISION IS A MYTH
Visual acuity is only one piece of the eyesight puzzle. While seeing clearly and sharply is one of the most important aspects of good vision, a 20/20 score doesn't mean you have perfect vision. The ability to perceive movement, sense visual peripheries, and see color all affect the quality of your sight.
With 20/20 vision, you might not need glasses to see clearly, but that doesn't mean you shouldn't stay aware of visual problems that might arise. Schedule regular eye exams to test your visual acuity, and don't forget to ask your eye doctor to check for glaucoma and cataracts to keep your vision as clear as possible.