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From worse than -3.0 to -2.5 and continuing
#11
SCHOOL NUMBER - BETTER EYESIGHT
A MONTHLY MAGAZINE DEVOTED TO THE PREVENTION AND CURE OF IMPERFECT SIGHT WITHOUT GLASSES - AUGUST, 1927

Demonstrate
That glasses lower the vision.
Stand fifteen feet from the Snellen test card and test the vision of each eye without glasses.
Then test the vision of each eye with glasses on, after having worn them for half a hour or longer. Remove the glasses; test the vision again and compare the results. Note that the vision without glasses becomes better, the longer the glasses are left off.
Test the eyes of a person who is very nearsighted. Remove the glasses and test the sight of each eye at five feet, nearer or farther, until the distance is found at which the vision is best without glasses. Now test the vision for five minutes at this distance, which is the optimum distance, or the distance at which the vision is best. For example, near-sighted people see best when the print is held a foot or nearer to the eyes. If the eyes see best at six inches, the optimum distance is six inches; but if the distance at which the eyes see best is thirty to forty inches, the optimum distance is then thirty or forty inches.
In near-sightedness, glasses always lower the vision at the optimum distance. The same is true in far-sightedness or astigmatism. For example, a near-sighted person may have an optimum distance of six inches. If glasses are worn, the vision is never as good at six inches as it is without them. This demonstrates that glasses lower the vision at six inches, or the optimum distance in this case. In far-sightedness without glasses, the optimum distance, at which objects are seen best, may be ten feet or further. If glasses are worn and the sight is improved at the nearer point, the vision without glasses at the optimum distance becomes worse.
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Re: From worse than -3.0 to -2.5 and continuing - by clarknight - 10-14-2011, 11:25 AM