What Is 20/20 Vision?

August 09, 2012

You must have heard many people saying I have 20/20 vision. But do you know what the actual meaning of this term is?20/20 vision is nothing but normal visual acuteness. The numbers used in this express the feet on the basis of which visual acuity is measured. If 6/6 is used it means 6 feet distance is used to measure visual acuity. Visual acuteness means your ability to see things and people clearly from a particular distance. 20/20 rule means you can see things as clearly from 20 feet distance as a normal person can see. To check this Snellen chart is used that has rows of letters turning smaller towards the bottom. It has different numbers ranging from 20/10 to 20/200.

What the value is of numbers in 20/20?

In 20/20 chart some numbers are defined in which top numbers signifies the distance at which the person being tested stands form the eye chart and the bottom number signifies the distance of a person with normal vision from eye chart and his ability of reading the letters.

In this higher the number poorer will be the vision of the person. For example if number is 20/200 it is poorer than normal vision, because the person with poor vision needs to be only 20 feet away from the chart to read the letters that a person with normal vision can read from 200 feet away. In contrast a person with 20/10 has better vision as compare to normal vision. He will be able to read from 20 feet away for which a normal person will have to go 10 feet away to read. The eye charts in doctor's office are made accordingly to fit the room wherein you don't need to move away but the fraction mean the same thing.

What is The Snellen Eye Chart?

Dutch ophthalmologist Dr. Herman Snellen invented one eye chart in 1862 that become the most commonly used eye chart. The eye chart used for testing the vision is named after Dr. Herman Snellen. Some other tests called Tumbling E, the Broken Wheel and the ETDRS were also invented. Some tests were found for small children and adults who are unable to read.

• In the Tumbling E chart capital E is used facing all the directions and the person being tested has to respond as per the direction of E.

• In the Broken Wheel test cards with different pictures are used. These cards have pictures of cars and wheels with different conditions like broken or whole wheel.

• The ETDRS means Early Treatment of Diabetic Retinopathy Study which was developed for early treatment of Diabetic Retinopathy. It also uses letters but considered more precise than the Snellen chart.

20/20 Does Not Assure Overall Perfect Vision

As these measures are focused on only visual acuity they don't assure you of not having any other eye problem. It is possible that you have 20/20 vision but still you find it difficult to see close objects. You may also have other problems like poor depth perception, poor focusing power or bad peripheral vision. Most of the time people have separate score for both the eyes.

Best Corrected Vision

There are different options available to you to get best corrected vision. You can use glasses or contact lenses to get visual acuity. One more or say best option is use get Wavefront-guided Lasik surgery done. Surgery is best because it can correct slight defects in your vision that cannot be done while using corrective lenses or glasses.

What Is The Importance of Vision Scores For You?

There are different scores set for you to do a particular work. If you are going to get a driver's license its important to know that 20/40 is considered worst score you are allowed to have when you want to get a clear driver's license. For many professions this has been limited to 20/50. Even you cannot declare yourself to be blind even after having 20/200 vision score if you don't meet with the criteria set by the doctors.

How to Get 20/20 Vision

If you have 20/20 vision but still you face some vision issues or you don't have 20/20 vision, in both the cases you should consult your eye doctor. They can give you the better suggestion whether you should use glasses and contact lenses or you should go for a surgery.

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