Normal eyesight is defined as 20/20 vision.
What is Normal Vision?
When people talk about having "normal" vision, they are typically referring to 20/20 vision. This benchmark is used by eye care professionals to measure visual acuity, which is the sharpness and clarity of your vision. It indicates how well you can see at a specific distance compared to what is considered average or normal.
Understanding 20/20 Vision
According to the standard definition, 20/20 vision is considered ``normal'' vision. This standard comes from the Snellen eye chart test.
Here's what the numbers mean:
- The first number (20): This represents the distance in feet you are standing from the eye chart during the test. In many other countries, this is measured in meters, so 20 feet is equivalent to 6 meters (6/6 vision).
- The second number (20): This represents the distance in feet at which a person with normal vision can read the line you are reading.
Putting it together, 20/20 vision means:
You can read at 20 feet (6 meters) the smallest letters on the eye chart that a person with normal vision should be able to read.
Essentially, if you have 20/20 vision, you can see clearly at 20 feet what an average person can see clearly at 20 feet.
Is 20/20 Vision Perfect?
While 20/20 vision is the standard for normal visual acuity, it doesn't mean your vision is "perfect." Visual acuity is just one aspect of overall vision. Other important factors include:
- Peripheral awareness
- Depth perception
- Color vision
- Eye coordination
Someone can have 20/20 vision but still have issues with one of these other visual skills.
Comparing Visual Acuity
Visual acuity can be better or worse than 20/20.
- Better than 20/20: Some people have vision like 20/15, 20/10, or even 20/5. This means they can see clearly at 20 feet what most people would need to be 15, 10, or 5 feet away to see clearly. For example, someone with 20/15 vision can see at 20 feet what a person with 20/20 vision can only see at 15 feet.
- Worse than 20/20: If your vision is 20/30, it means you need to be 20 feet away to see something clearly that a person with 20/20 vision could see clearly from 30 feet away. The higher the second number, the poorer the vision.
In summary, normal eyesight is defined as 20/20 vision, representing the ability to see details at a standard distance equivalent to the average population.
