20-20 Vision

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Like many people, I have myopia or short sightedness. I can see things that are only two or three inches from my face, but I can’t recognize my wife across the room.

Myopia is caused because the distance from the lens at the front of the eye, to the retina at the back, is greater than normal. This causes images to focus in front of my retina. Fortunately, my problem can easily be overcome with corrective lenses, which make the light rays converge exactly on the retina, producing a sharply focussed image.

People with normal vision are described as having twenty/twenty vision. On the basis of a substantial number of eye examinations, eye doctors have been able to determine what normal people should be able to see when they stand twenty feet away from the eye chart. 20/20 vision means that your vision is typical of what ‘normal’ people would see when they too stand twenty feet from the optometrist’s chart.

20/30 vision means that at twenty feet away from the eye chart, you see what someone with good vision can see when standing thirty feet from the eye chart. 20/20 is not necessarily perfect vision. A person with 20/10 vision can see from twenty feet away what the average person can only see by standing ten feet from the chart. The hawk might even have vision eight times better than yours, say 20/2 vision!

So next time you think you have good eyesight, think hawks, and quit bragging!