20/20 vision is NOT perfect visionĢ0/20 vision is just the visual acuity of the average individual. For example, if you have 20/50 vision, it means that your vision is worse than average and that at twenty feet away, you can read the letters that most people can read from 50 feet away. The number on the right of the “/” symbol is the distance at which a person with normal eyesight can read the letters in the same line. The number on the left of the “/” symbol is your distance in feet from the chart, kept constant at 20 feet (or around 6.1 metres). Notice the numbers on the extreme right side of the chart, such as 20/40 and 20/70? They are the visual acuity measurements, also called Snellen fractions. This is how you determine if you have 20/20 vision. Eye charts like these are used to evaluate what an individual’s visual acuity is. The chart was named after Herman Snellen, the Dutch ophthalmologist who created this system in 1862. If you have been to the optometrist or ever had an eye examination (which you should be getting regularly!), you will be familiar with the Snellen eye chart, like the one pictured above. In other words, someone with 20/20 vision can see what an average person can see when they are standing 20 feet away. If you are lucky enough to have 20/20 vision without any corrective eyewear, it means that you are able to see things clearly at 20 feet away what should normally be seen at that distance. 20/20 vision is a term used to express normal vision or normal visual acuity (how clear or sharp your vision is).
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