IN the chapter on "The Imperfect Sight of the Normal Eye" it was seen that no refractive condition is ever continuous. Eyes with ordinarily normal sight may suffer from errors of refraction at times, and eyes which are ordinarily near-sighted or far-sighted or astigmatic, may become less so, or even normal. It is obvious that this must be so, from the fact that the refraction is controlled by muscular action. But glasses cannot change as the eyes change, and therefore the mind, which wants to see, and which has a great capacity for adapting itself to adverse conditions, tries to maintain continuously the refractive condition they are designed to correct. That this tires the eyes is the experience of everyone who has worn glasses; that it must make the condition worse is obvious; and that it must be particularly harmful during the plastic years of childhood goes without saying.
The thing to do if one has an error of refraction, therefore, is not to wear glasses but to learn how to use the eyes correctly. This means seeing best with the center of sight, the fovea centralis previously alluded to, and this means that a very small part of everything one looks at is seen best and everything else less distinctly in proportion as it is removed from the central point. This is called Central Fixation and is the basis of the treatment of errors of refraction without glasses. When the eye looks at objects with central fixation it is at rest, the muscles which control the refraction act normally, and maximum vision is attained.
In the upper picture the sight is centered upon one spot, the upper left-hand corner of the letter R, which is seen more clearly and appears to be blacker than the rest of the field of vision. This is central fixation. In the lower picture the subject is endeavoring to see every part of her field of vision equally well at the same time. This is eccentric fixation and always accompanies eye strain.
It is impossible, however, for the eye to look at any point for more than a fraction of a second. If it tries to do so, the point disappears and the whole visual field blurs. Perfect vision is thus seen to depend on clear vision of the smallest possible area and constant movement of the eye from one such area to another.
Central fixation is opposed to Eccentric Fixation, in which the eye partially or completely suppresses the vision of the center of the retina and sees a considerable area all alike at one time, or even sees the outer part of the visual field better than the center. In such cases not only is the central point seen less distinctly than it normally should be, but the outer parts of the field are less distinct than when the center is seen best. Black letters appear less black, white letters upon a black ground less white, and colored letters of a lighter shade than they normally would. The outlines of the letter are not clear, the margins being shadowy. Their size is altered and they appear larger or smaller than with normal vision. Their shape is distorted, and a square letter may seem to be round. Illustrations of various kinds occur, and multiple vision is common. Pain, fatigue, or discomfort of some sort is usually felt, and headaches are frequently produced.
A common symptom, also, is twitching of the eyeballs or eyelids. This is usually unconscious, but may be felt if the patient lightly touches the closed eyelid of one eye while the other is looking at a letter by eccentric fixation. The appearance of the eye is usually expressive of effort, and a greater or less degree of squint is always present. Even redness of the margins of the lids and dark circles under the eyes may be produced by eccentric fixation.
Most people whose vision is not markedly defective can demonstrate the facts of central fixation for themselves. Let such a person try to see two printed words, or even two letters, equally well at the same time. At first he will probably find himself looking from one word or letter to another, and if he really tries to see both at the same time he will find it so difficult that he may give it up before anything happens. If he is able to keep up the strain for a very brief period, however, the words will blur and become indistinguishable. If he is able to look at a small letter, however, and see it better than the others in its neighborhood, or look at one side of the letter and see it better than the other he will experience a feeling of rest.
Eccentric fixation is a symptom of strain (in which the whole body participates). The first thing for the patient who wants to improve his vision to do, therefore, is to relax this strain. One of the best ways to do this is to close the eyes, cover them with the palms of the hands in such a way as to exclude all the light, while avoiding pressure on the eyeballs (see illustration), and think of something that will keep the mind at rest. Many people like to remember something black, but any other color will do just as well if one prefers it. It is necessary to shift the attention from one part of the remembered object to another, because, as any psychologist knows, it is impossible to be continuously conscious of an unchanging object, and if one tries it he will only increase the strain. With practice it becomes easier to think of very small objects, like a period, or a very small letter, but in the beginning most people prefer something fairly large. One can also for a change think of other things, but the memory of a small object of vision seems to produce the best results.
These periods of rest may be as long and as frequent as time and inclination permit. A few minutes will help, but a half-hour period, two or three or more times a day, is usually necessary for adults. Some people are more greatly benefited by an hour, or even several hours; but it is useless to attempt these long periods unless one can do it without becoming mentally worried or physically restless. In that case they become periods of strain, not periods of rest. The ability to relax in this way grows with practice.
After the eyes have been rested by palming, or by simply closing them, one should look at the letters of the Snellen test card, or at a bit of reading matter which one could not see before, and almost invariably he will find that his sight has improved, sometimes only slightly, sometimes to an astonishing degree. Occasionally this improvement is permanent, but usually it lasts for a moment only. This is the germ of improved vision from which the full flower of normal sight must grow. As soon as the strain returns, and the vision begins to lapse to its old condition, one should rest again for as long a time as is found necessary, and proceed as before. If one keeps up the practice, the flashes of improved vision come oftener and stay longer until at last they become permanent. In reading the letters on the test card one should, of course, never stare at them. If one does not see a letter, he should immediately look away, close the eyes, or palm. If one does see it, and wants to go on looking at it, he can shift from one side of it to the other.
Between periods of regular practice one can rest by closing the eyes for a moment or longer, as occasion permits, with or without the memory of a period or other small object, and sometimes one has an opportunity to palm with one hand. And one can practice on the letters of advertisements and signs, or on any small objects in one's line of vision. Some people think they are benefited by carrying about with them continually the memory of a period or small letter, but others find it a strain to remember such an object with the eyes open.
Another way to obtain central fixation is to notice that one sees a part of everything he looks at best, and the rest of it less distinctly in proportion as it is removed from the central point. The Snellen test card is useful for this practice. One can begin by looking from one end of a line to another, noting that he sees each best alternately. Then he can look from one letter to another and finally he may become able to look from one side to another of the smallest letters at a distance of ten or more feet and see each side best alternately.
A good way to practice at the near-point is to make a dot of about the size of a pica-type1This book is printed in pica type. period, and after finding the distance at which it is seen best, try, by the methods given above, to bring it out with equal clearness at greater and lesser distances. By daily practice it should become possible to see it clearly as close as three inches and as far away as twenty. Or one may do the same thing with diamond type.
When the eyes are different it is best to begin practicing both together. Later, if it is found necessary, the eye farthest from normal can be practiced separately and to a greater extent.
Diamond type is condemned by most Opthalmologsts and Optometrists as being too fine for any eye except under most favorable conditions. My experience has been that considerable benefit can be derived from reading this because it practically necessitates central fixation. It cannot be read except when the eye is relaxed.
Many Bibles and Testaments are printed in Pearl type. This small print is considered by some to be responsible for much eye weakness, but we can prove that the eye defects are the results of other causes than the small print.
It is claimed by the secretary of one of the State Boards of Health that an attempt of a boy to read a Bible printed in Agate type caused the eyes to be so weakened that school work was abandoned for two years I claim other causes were instrumental in producing this eye weakness.
Nonpareil is used for some papers and children's magazines, but is condemned by those who have a wrong idea of the use and abuse of the eyes.
It is claimed that Minion may be safely used by adult or young eyes, though it is, erroneously, considered injurious for children.
Brevier is frequently seen in newspapers. This should be a satisfactory type for anyone.
Bourgeois is a favorite type for magazines and is very similar to Brevier.
And in all cases it should be kept constantly in mind that the sight cannot be improved by effort. Strain cannot be relieved by effort, but only by "letting go."
In addition to the foregoing practices everything possible should be done to relax the mind and the whole body. It is well to begin the day with general bodily exercises. A warm or tepid sponge bath, followed by a cool or cold sponging and brisk rubbing with a rough towel, will help to maintain normal skin action. A cool eye bath, gradually growing a little cooler, but never cold enough to be uncomfortable, is an excellent local treatment for the eyes. One should take whatever measures are necessary to secure normal action of the bowels. A daily walk as long as time and strength permit, introducing short runs at intervals, will prove a great benefit unless there is some contra-indication in the way of serious disease. Increased vitality is needed for health of body and eyes, and it cannot be obtained without exercise, taken in gradually increasing doses. One should breathe fresh air all night and every hour possible during the day. One should obtain sufficient sleep if one hopes to have normal eyes.
These measures are usually successful in curing myopia, hypermetropia, astigmatism and presbyopia. Patients with presbyopia, combined with other errors of refraction, and even incipient cataract, have been cured at sixty, seventy and even eighty years of age. Persons with high degrees of myopia have been cured by practicing only a few of the directions presented here. It is not necessary to understand anything about the anatomy and physiology of the eye—however interesting and useful it may be to know these things—to be cured of errors of refraction. All that is necessary is to follow, literally and persistently, the simple directions given, every day for a sufficient length of time.
Glasses should be discarded if possible. Some people are able to make progress in spite of wearing them part of the time, but they are always a great handicap, undoing, to a greater or less degree, what has been gained by practice. If worn without change after the refraction has changed, they may also cause great discomfort.
If the methods recommended later for the prevention of myopia in schools were practiced by people generally, whether they are old or young, or whether their eyes are good, bad or indifferent, that one thing alone would be of inestimable benefit. If any child under twelve who has never worn glasses reads the small letters of the Snellen test card, or any small letter, every day, or letters, at a distance of ten feet or more, with both eyes together and each eye separately, he will be cured of errors of refraction in from three months to two years, without any supervision or any other treatment. Adults of all ages will also be benefited by this practice, and may be cured, if they are sufficiently persistent. By such practice both children and adults will usually discover for themselves the facts about central fixation, strain, and other fundamental truths about the eyes.
The time required for a cure varies greatly in different cases. Some persons are relieved immediately. In other cases weeks, months and even years of training are required. The practice should always be continued for a few minutes daily to avoid relapses. Even the normal eye requires practice in normal vision to avoid falling into errors of refraction.