Did you know?  Two patients today asked me what 20/20 vision means. I suspect that every day other patients wonder as well, but don’t ask.The easiest way to think about 20/20 is that it means that the eye can see at 20 feet what the average, healthy eye can see at 20 feet. It would follow that 20/200 (poor) vision means that the eye can see at 20 feet what an average, healthy eye can see at 200 feet, or that an eye that sees 20/10 (exceptionally well) sees at 20 feet what an average, healthy eye can see at 10 feet.

Having 20/20 vision does not necessarily mean that your eyes are healthy. The presence of glaucoma or many other eye conditions may not affect central visual acuity until late in the disease. Healthy eyes, though, usually do see 20/20 or better.

If an eye does not see 20/20, it is up to the ophthalmologist to determine the cause. It is also important to test each eye individually.

Did you also know?  The standard eye chart used by most doctors today is known as the Snellen Eye Chart, developed by Dutch ophthalmologist Herman Snellen in 1862.

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