2020 vision

2020 vision is defined as the ability to read the smallest letters that an average healthy adult can see at a distance of 20 feet. Essentially, it represents standard visual acuity. If someone has vision that is not 20/20, it could be worse (e.g., 20/25, 20/40, etc.), meaning they can only read at 20 feet what a typical person can read from a greater distance. On the other hand, some individuals might have better than normal vision, such as 20/15 or 20/10, which means they can see from 20 feet what others would need to be closer to see—this is sometimes found in athletes or those who have undergone certain types of eye surgeries like LASIK 1.

Exploring further into visual acuity, it is commonly consistent between both eyes in healthy individuals, and we start life with a much lower acuity (e.g. 2200 as infants), which improves as we grow older. The highest acuity is in the center of the visual field, with peripheral vision being much less clear. Interesting to note, certain animals, like hawks or owls, naturally have much sharper vision compared to humans 2.