20/20 is a term that describes how small you can read and at what distance. It’s equivalent to 6/6 in metric. 20/20 is the ability to read 20pt characters at 20 feet, and 6/6 is 6mm characters at 6 meters. They are also called Snellen fractions, named after Herman Snellen who created the measurement system in the 19th century.
20/20, or 6/6, however, is not perfect vision. It simply means normal or optimal visual acuity. Visual acuity is the sharpness of your vision. This measurement describes exactly how sharp your eyes are, by testing how small you can see at a certain distance. This is the test they use to see what kind of glasses you need at an optometrist office. They will isolate one eye, and cycle through many different lenses, asking you along the way, which one is the best. This is how optometrists narrow down your vision to figure out what kind of lens is required for the best possible sight you can have.
It is possible to have better vision than 20/20, such as 20/15 or 20/10, the latter of which means your eyes have double the sharpness of 20/20 vision. It is also possible to have much it much worse, at 20/40 and even up to 20/200.
Is it Possible to still Need Glasses Even with 20/20 Vision?
So now that we have a basic understanding of the 20/20 measurement, is it possible to still need glasses even with 20/20 vision? Well, glasses are needed for a variety of reasons. Excluding sunglasses, people with dyslexia and astigmatism may require prescription glasses. There are also special glasses with high definition lenses to give people with 20/20 vision even better focus.
The more important question is if you need better than 20/20 vision, and for what purpose. A sports athlete may not care about how much his eyes focus, but more about the speed at which they can discern information, for fast-moving objects. This can also change for different coloured objects and how an artist or painter interacts with them. Acuity is not the only measurement that matters, and its not reflective of your vision in other circumstances.
So can you still need glasses and have 20/20 vision? Of course, depending on your situation and what you want to accomplish. Getting a regular checkup at your optometrist should be a part of everyone’s life, and can not only help your vision but help detect and prevent eye disorders.