Every school, private and parochial as well as public, should supply itself with the Snellen card for testing eyes. Employers would do well to have these cards in evidence also, for they may greatly increase profits by decreasing inefficiency and risks. If there is no expert optician near, apply for cards to your health board or school board; failing there, write to your state health and school boards. In many states rural teachers are already supplied with these cards by state boards. In October, 1907, the New York state board of health sent out cards, with instructions for their use, to 446 incorporated towns. The state commissioner of education also sent a letter giving school reasons for using the cards. Results from 415 schools having shown that nearly half the children had optical defects, it is proposed to secure state legislation that will make eye tests obligatory in all schools. Such a test in Massachusetts recently discovered twenty-two per cent of the school children with defective vision, and from forty to fifty thousand in need of immediate care by specialists.
POSITIONS OFTEN SUGGEST EYE STRAIN
Of course eye specialists,—oculists,—if skillful, know more about eyes and eye troubles than general medical practitioners or teachers. Preliminary eye tests, however, may be made by any accurate person who can read. The Massachusetts state board of health reports that tests made by teachers were "not less efficient" than tests made by specialists. In June, 1907, a group of eminent oculists recommended to the school board of New York City that teachers make this first test after being instructed by oculists. Persons interested in the schools nearest them can quickly interest teachers and pupils by starting tests with this card. In cities oculists can be found who will be glad to explain to teachers, individually or in groups, how the cards should be used and what dangers to avoid.
Nature intended the human eye to read the last line of this card at a distance of ten feet. This conclusion is not a guess, but is based upon the examination of thousands of eyes. In making the test, the number of feet the eye ought to see is written as the denominator of the fraction; the distance the eye can see clearly is the numerator. If the child's card reads, "Right eye 10/10, left eye 10/20," it means that the right eye sees without conscious strain the distance it is intended to see, while the left eye must be within ten feet to see what it ought to see twenty feet away.
The practical steps for a teacher to take in making eye tests are:
1. Scrutinize the faces for a strained or worried expression while reading or writing, for squint eyes, for unnatural positions, and for improper distances (more or less than nine inches) from eye to book.
2. Select for first tests the children who obviously need attention and will be obviously benefited. Use the eye test to help trace the cause of headaches, nervousness, inattention.
3. Let the children mark off the distances with a foot rule and chalk, going as high as twenty. Be sure to get the best light in the room.
4. Start all children on the ten-foot line. If a child cannot read at ten feet the letter which should be seen at that distance, move the child forward, have it step forward and backward, and note the result carefully. It is better to have ten separate letters of exactly the right size and the same size than a row of letters on one card, as in the Snellen test, otherwise memory will aid the eye, or, as happened recently, a whole class may agree to feign remarkable nearsightedness or farsightedness by confusing letters learned in advance from the card. If the Snellen card is used, and if it is more convenient to have both child and card stationary, satisfactory results will be obtained by having the child read from large letters down as far as he can see.