If you have 20/20 vision, you can see objects 20 feet away from you that a normal-sighted person can see at the same distance. (By “normal-sighted”, we mean someone who has 20/20 vision without wearing contact lenses or glasses.) What 20/20 vision really means: This is also the distance at which a normal-sighted patient can see the same size object. The denominator tells you at what distance the letter on the chart was designed for. The numerator of the 20/20 fraction denotes 20 feet, because 20 feet is the standard for distance vision measurement. Your recorded vision is the smallest line you can see. The letters get smaller as your eye travels down the chart. ![]() The ‘Big E’ is situated at the top of the chart. įor this reason, the letters on the Snellen Chart are not only a specified size for each line, but have very precise construction and spacing between letters. It also specifies that the minimal amount of your visual field involved would create at least 1′ of arc. This theory states that in order for you to recognize an object, a minimal area of your retina needs to be stimulated. The letters on this chart are constructed based on the Hemholtz theory. Here’s a little more detail on 20/20 vision:Ī Snellen eye chart, or projector, quantifies visual acuity which is a measurement of the sharpness of vision. ![]() The simple answer is that 20/20 vision is a standard for the measurement of visual acuity and represents ‘normal’ or average vision. But, what does that really mean? We hear this question a lot at Mandel Vision. We’ve all heard the term ’20/20 vision’ and most of us know that this is considered ‘normal’ vision.
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