If you’ve ever been to an optometrist or eye doctor, you’ve likely heard the phrase “20/20 vision.” You may have even heard that having 20/20 vision is considered “normal” eyesight, but what does it really mean? In this blog, we’ll explore the origins of the term and what it actually means for your vision.
The concept of 20/20 vision dates back to Dutch ophthalmologist Herman Snellen who created the Snellen chart in 1862. The Snellen chart became a standard tool used by eye doctors for measuring visual acuity or sharpness of vision. It consists of 11 rows of capital letters (from top to bottom) that decrease in size as well as five columns (from left to right) with increasing letter size at each step. The most familiar row of letters read “E-F-P-H-A-S-T-C-O-L” across the top row from left to right.
The numbers associated with 20/20 vision refer to visual acuity measurements based on how far away an object can be seen clearly; someone with 20/20 vision is able to see something clearly from a distance of twenty feet away. This is considered normal visual acuity and means that your eyes are functioning properly and you don’t need corrective lenses for nearsightedness or farsightedness. It doesn’t necessarily mean that you have perfect eyesight; rather, it simply means that you can see things from a distance as well as someone with normal eyesight would be able to see them.
If your visual acuity falls below 20/20, this means that your eyes require corrective lenses in order to achieve optimal clarity when viewing objects from a distance. For example, if your visual acuity is measured at 20/40 then you need glasses in order to read an object at twenty feet away that someone with perfect eyesight could read from forty feet away. Similarly, if your visual acuity is measured at 20/60 then you need glasses in order to read an object at twenty feet away that someone with perfect eyesight could read from sixty feet away.
In conclusion, 20/20 vision refers to normal visual acuity and measures how well someone can see objects from a distance without corrective lenses or contacts. Although having 20/20 vision does not necessarily indicate perfect sight, it does indicate good eyesight overall and suggests that no corrective lenses are necessary for seeing clearly at a distance. Those who do not have this level of normal visual acuity may require corrective lenses such as eyeglasses or contact lenses in order to achieve optimal clarity when viewing objects from afar. Thanks for reading! We hope this article has helped shed some light on what "normal" eyesight looks like and why it's important!