What is the meaning of 20 20 Vision?
Furthermore, why is it called 20/20 Vision?
Snellen charts display letters of progressively smaller size. "Normal" vision is 20/20. This means that the test subject sees the same line of letters at 20 feet that person with normal vision sees at 20 feet. 20/40 vision means that the test subject sees at 20 feet what a person with normal vision sees at 40 feet.
Additionally, can you have 20 20 Vision and still need glasses? Since acuity tests only measure one aspect of vision, people with 20/20 vision may still require glasses. According to Dr. Aizuss, "Patients who are middle-aged—early 40s and older—may still have excellent uncorrected distance vision but require glasses for reading.
Considering this, what is perfect eyesight?
Visual acuity of 20/20 is considered “perfect vision” because no aids are required to see better, but people can have better than 20/20 vision. Many young people are able to see letters smaller than the general “20/20” size.
What vision is legally blind?
Most government agencies and health care institutions agree that legal blindness is defined as a visual acuity (central vision) of 20/200 or worse in the best seeing eye or a visual field (peripheral vision) that is limited to only 20 degrees.