Most of us have heard of 20/20 vision, but do you actually know what it means? Despite what many people assume, 20/20 vision is not perfect vision, but rather normal vision!
Most of us have heard of 20/20 vision, but do you actually know what it means? Despite what people commonly assume, 20/20 vision is not perfect vision, but rather normal vision!
20/20 vision is defined by normal vision acuity. An eye chart measures visual acuity, the clarity or sharpness of vision. The top number refers to distance (in feet) from the chart. The bottom number indicates the distance at which a person with normal vision can read the same line.
If you have 20/30 vision, your vision is worse than average. It means that you are standing 20 feet from the chart, but you can read letters that those with normal vision can see at 30 feet away.
Typically the goal of correcting vision with glasses or contact lenses is to bring a person’s vision to 20/20. According to the National Health and Nutrition Examination Survey, only 35% of adults have 20/20 vision without glasses/contact lenses or corrective surgery.
To help reach 20/20 vision, glasses or contact lenses are used to help correct refractive errors. The most common refractive errors are nearsightedness (myopia), farsightedness (presbyopia) and astigmatism.
- If you are nearsighted, you have difficulty seeing distant objects clearly, but can see up-close objects well.
- If you are farsighted, you may have trouble seeing things at close range, but can see distant objects well.
- If you have an astigmatism, it means that light fails to come to a single focus on the retina, and therefore vision is blurred to distorted to some degree at all times.
If you’re experiencing any issues with your vision, be sure to inform your eye care provider.