How to Use the Snellen Test Card for the Prevention and Cure of

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The Snellen Test Card is placed permanently upon the wall of the
classroom, and every day the children silently read the smallest
letters they can see from their seats with each eye separately, the
other being covered with the palm of the hand in such a way as to
avoid pressure on the eyeball. This takes no appreciable amount of
time, and is sufficient to improve the sight of all children in one
week and to cure all errors of refraction after some months, a year,
or longer.

Children with markedly defective vision should be encouraged to read
the card more frequently.

Records may be kept as follows:

John Smith, 10, Sept. 15, 1918.
R.V. (vision of the right eye) 20/40
L.V. (vision of the left eye) 20/20

John Smith, 11, Jan. 1, 1919.
R.V. 20/30
L.V. 20/15

The numerator of the fraction indicates the distance of the test card
from the pupil; the denominator denotes the line read, as designated
by the figures printed above the middle of each line of the Snellen
Test Card.

A certain amount of supervision is absolutely necessary. At least once
a year some one who understands the method should visit each classroom
for the purpose of answering questions, encouraging the teachers to
continue the use of the method, and making a report to the proper
authorities.

It is not necessary that either the inspector, the teachers, or the
children, should understand anything about the physiology of the eye.

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