The general reason why many people wear eyeglasses or contacts is to achieve 20/20 vision. This is a standard that was set back in 1862 by Herman Snellen, a Dutch ophthalmologist, when he developed a measurement system for visual acuity. 20/20 vision is considered normal vision, but what does it really mean?
Understanding Snellen’s Eye Chart
Snellen’s eye chart is what is still used today to measure visual acuity, which is the sharpness of your vision. If you have 20/20 vision, you can see what an average person sees on the eye chart when they are standing 20 feet away from it.
If your eye doctor tells you that you have 20/30 vision, your vision is considered worse than the average person. When standing 20 feet away from the chart, you are reading letters that most people would be able to read from 30 feet.
So, Does 20/20 Vision = Perfect Vision?
It is possible to have 20/15 or 20/10 vision, which is even better than 20/20. Most of us do start out with 20/20. However, around the age of 8 or 9, our vision acuity changes, but it stays about the same until we reach our 60s or 70s. It is estimated that 35 percent of all adults have 20/20 vision without the need for vision correction. About 75 percent of adults can achieve 20/20 with glasses, contacts, or eye surgery.
Having 20/20 vision is just part of the equation to having perfect vision because it is only a measure of the sharpness of your vision at a distance. There are other important vision skills that need to be considered too, including:
- Depth perception
- Peripheral vision
- Eye coordination
- Color vision
- Ability to focus
You could be able to see objects clearly at 20 feet or further, but they have difficulty focusing on nearer objects. This could be because you are farsighted (hyperopia) or have a loss of focusing ability (presbyopia). If you develop presbyopia as you get older, you may eventually need reading glasses or bifocals. On the other hand, you may be able to see objects up close, but cannot see them far away, which could indicate you may be nearsighted (myopia).
Having 20/20 vision is great, but you do need a comprehensive eye exam performed by a vision professional to determine how good your vision really is. Call Valley Eyecare Center at (602) 955-2700 to schedule your eye exam today.