Also the measurement is using high contract- black letters on white background. Why? Well, 20/20 vision is measured statically for one- in other words while the person is not moving. Vision is a term that is too general to accurately describe what the 20/20 measurement denotes. While we tend to say “20/20 vision” a more proper term is 20/20 visual acuity. Why do you keep saying 20/20 visual acuity? If this is the smallest letter you can read WITH corrective lenses in front of your eyes, you are legally blind. The single “E” at the top of the chart represents 20/200 vision. If you can read the 20/10 line- your visual acuity is two times better than someone who can only read the 20/20 line. The smaller letters in lines below the 20/20 line correspond to better than 20/20 visual acuity.
The letters get larger as the lines go toward the top of the chart and each line corresponds to worse visual acuity. If you can identify the letters on this line, but none of the smaller letters on lower lines, you have 20/20 vision. At this distance, one of the smaller lines at the bottom of the eye chart has been declared the standard- to correspond with normal visual acuity. In the Snellen measurement system- the top number represents the distance between the person and the eye chart. Could he even have dreamed that 158 years later optometrists all over the US would be doing a happy dance that the year 2020 is going to be their year. Herman Snellen, developed the 20/20 measurement system for visual acuity in 1862. People are termed “legally blind” if their vision with glasses or contacts is 20/200 or worse.A Dutch ophthalmologist, Dr. Also, 75 percent of adults with less than 20/20 vision can have 20/20 vision after correction with glasses, contact lenses, or eye surgery. Glasses or contact lenses can help correct the vision to 20/20.Ībout 35 out of every 100 adults have 20/20 vision without using glasses, contact lenses, or have any eye surgery. It means they can see an object clearly that is placed 20 feet away when most people will need to be 15 feet near to the object to see it.Įven if a person does not have a 20/20 vision, they shouldn’t worry much. If a person has a 20/15 vision, they have a vision that is sharper than average, and it is normal to have one.This means that their vision is worse than average. If a person has 20/30 vision, it means that they need to be 20 feet near to the object to see it clearly when most people can see the same from 30 feet.A 20/20 vision means that a person has an average or normal vision.The result of this test could mean the following: The person will be asked to try reading the numbers from a 20 feet distance.
The test uses an eye chart called Snellen vision testing chart in which there are numbers. This is a simple test done by an optometrist or at an eye doctor’s (ophthalmologist) office to check eyesight. Visual acuity is a medical term for the clearness or sharpness of vision.
It means the person can see things clearly from a 20 feet distance as an average person would see from the same distance.Ī 20/20 vision is a way to measure visual acuity. Having a 20/20 vision means having normal vision. A 20/20 vision is a way to measure visual acuity.
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