Normal vision is often described as 6/6 vision, meaning you can see at 6 meters (20 feet) what a person with normal vision can see at 6 meters.
In simpler terms, the term "eye power" is usually understood as visual acuity. When measuring visual acuity, a person with normal vision, also called emmetropia, can clearly see objects at a distance of 6 meters without any corrective lenses (glasses or contacts). The test measures your ability to recognize letters or symbols of a certain size from a specific distance.
Here's a breakdown:
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6/6 (or 20/20): This is considered normal visual acuity. You can see what a person with "normal" vision can see at 6 meters.
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Values above 6/6 (e.g., 6/5): This indicates better-than-average vision. The person can see at 6 meters what a person with normal vision would need to be at 5 meters to see.
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Values below 6/6 (e.g., 6/12): This indicates poorer-than-average vision. You need to be at 6 meters to see what a person with normal vision can see at 12 meters. This typically means you need corrective lenses.
Therefore, 6/6 vision, or 20/20 in the imperial system, represents the standard for normal visual acuity.
