THE PHYSIOLOGY OF THE EYE
ORDINARILY we think of the eye in very simple terms. We realize a difficulty in seeing things, and we ask ourselves what we must do. The only remedy offered is to get what help we can from a pair of glasses. Very few ask any further questions. If they have heard of the Bates method, and inquire about it, they are informed, in a regular stock phrase that: "Dr. Bates has been discredited." There is a growing rebellion against that reply, which is not an answer. But only a few have access to the answer that is found in the success of those who have carried out the techniques of that method.
In a book by a psychologist of high standing it is pointed out and proved that physicians do not any longer try to make the distinctions that used to be made between organic and functional diseases. Conditions that were thought to be caused by a change in tissue structure, are now known to be caused by a fault in function, consequent upon improper nerve impulses, prompted by a disordered mechanism in the central control.
A famous biologist, in a recent book, writes that the illusions of the mechanists, and the childish physico-chemical conceptions of the human being, in which so many physiologists and physicians still believe, must be definitely abandoned. That the mind, hidden within the living matter, is completely neglected by physiologists, and almost unnoticed by physicians.
The use of spectacles is often a necessity. But a claim that such a mechanical device has any value as a correcting influence upon the mechanism of vision is surely the theory of a mechanist. There is no claim made that the glass lenses have any influence upon the abnormal conduct of the visual center. The only claim is that they help some to see by using the glass lens instead of using the lens of the eye.
Everyone knows that there is a constant mental activity which is outside the circle of our awareness. This storehouse of endowment and life-long development is the power-house which impels every function of life. It provides the energy for conscious thought and conscious action, and dominates every vital process of the body. The mechanism of vision is part of its dominion. The muscles which change the shape of the eyeball, and the nerves which carry the force sent in by radiant energy, and the impressions which are made upon the brain cells of the visual center, comprise the mechanism of vision. The mind interprets images. The mind includes memory, experience, judgment, imagination. All of these are involved, and are vitally active, and upon them depend the power of vision, and the truth of the impressions and the conceptions of which we are conscious by reason of the images that the eyes receive.
A well known professor of psychology carried out a most ingenious experiment which has a direct bearing on the subject matter of this chapter. His remarkable demonstration illustrates how much of the function of vision is carried out by that part of the brain which is called the visual center. It shows also, very clearly, the complexity of the question of the value of artificial lenses. It explains how they frequently hinder the effort to see instead of helping the difficulty.
The picture thrown upon the retina of the eye is always reversed perpendicularly and laterally. In order to realize the significance of this statement, it must be remembered that the light rays reflected from the upper part of the object looked at slant downward so that they are delivered onto the lower part of the retina, which is the receiving film of the eye; and the light reflected from the lower part of the object is likewise delivered onto the upper part of the retina. Objects on the right side would be represented as on the left, and vice versa. This is partially realized by looking into a mirror.
It is easy enough to imagine the disturbance and confusion which would be caused by such a complicated misrepresentation of everything, in the complete reversal of the positions of every object seen. But the human visual receiving apparatus corrects this perfectly. In what manner that wonderful transformation is accomplished, the mind of man has not learned how to explain.
This professor of psychology prepared a pair of glass lenses which so refracted the light rays that the image was already inverted before it reached the lens of the eye. The lens of the eye refracted the rays received just as it had always done. This had the effect of delivering the image onto the retina right side up, and laterally also without being inverted. As a result, all objects at first were seen by the mind inverted perpendicularly and laterally. This was because the habit of the mechanism of vision treated the seen objects in the accustomed automatic manner, and re-inverted the images received. Wearing the deceptive lenses all day, the eyes were covered at night. The wearer at first had a unique experience. He would collide, for instance, with objects which seemed to be on the right, but were on the left. Hut in the course of a week a new mechanism of adjustment had been built up, by changing, somehow, the various reactions of the brain cells in the visual center. Then things seen were again presented as they had been before, despite the complete reversal still presented by the glass lenses.
This necessitated some new functioning of the different parts of the complex higher visual mechanism. Something was done which the brain and the mind had never done before. Something of a nature essentially different from the mere physics or optics of lenses—glass or flesh. The brain, might we Say, working for the mind, met the emergency as just another one of the discrepancies which are constantly being imposed upon our different organs, and generally compensated with success.
When the brain—or shall we say, the subconscious mind had fully accomplished the necessary readjustment, and images were again habitually seen correctly, the trick lenses were re moved. The mechanism of vision continued for a time to follow the newly devised method or system, and things were again in confusion. This time however, the new condition lasted only a few hours. The old, natural habits promptly dismissed the strange interlude, and went to work again in the inherent, accustomed way.
Suppose we consider for a moment, deliberately, something of the plain import of this most ingenious experiment. It has taken us up into the higher, more vital functioning of the mechanism of vision. But it has also made plain some most important direct considerations. When rays of light fall upon the retina, they produce chemical changes which alter what is called radiant energy into some different form of energy, some different kind of nerve stimulus. It is this new force which acts upon the brain cells. When a person is nearsighted—so-called—all light rays do not fall exactly upon the retina, because the eyeball is too long, and the rays reflected from farther objects meet too soon. In a far-sighted person it is just the opposite. The eyeball is too short, and rays focus behind the retina, which acts like a film. When the eye is impaired with astigmatism, the eyeball is more or less out of shape, instead of being a perfect sphere, and that influences in an abnormal manner the direction of the different rays of light. This is the explanation given in the text books.
Now, in the experiment just described, the rays of light received upon-the given retina were not imperfectly focused; they had been so completely changed in their directions that the image received was exactly reversed in detail from what should have been received, and always had been received as a picture of a given object. That part of the mechanism of vision which is beyond the retina interpreted, deciphered, corrected the deception, and acquired the necessary visional information in such manner that the impressions were the same as if the lenses described had not been used at all.
This experiment demonstrated, therefore, that the subconscious mind can accommodate itself perfectly to an experience not only strange, but actually a misrepresentation, compared to the manner in which the information had hitherto been presented.
The pair of eyes used for this demonstration by a famous psychologist were governed by a visual center in the brain which was working normally. Aroused to an alert attention by such a remarkable challenge, the mentality of the subject rallied its trained resources of memory and imagination, and judgment, and learned the answer. The mind knew that things were not upside down. In that experiment the mind knew that the false lenses caused the trouble. It was the mind that taught the mechanism of vision how to change its habit of the ages. The mind ordered that mechanism not to re-invert the strange images received on the retina. The unconscious part of the mind knew how that function was performed, although the conscious part of the mind did not. It was the unconscious part of the mind that accomplished the victory over the false lenses. This was possible because the conscious mind was aware of the interference and willed to overcome it.
That wonderful demonstration is surely worth some consideration on the part of those who offer lenses as the only possible relief for eyes that are troubled with some slight abnormal function on the part of the same mechanism. A doctor who had worn glasses for years on account of astigmatism, asked if I really claimed that the Bates method would cure astigmatism. I am sure he did not accept my explanation, because it did not agree with his own ideas. The explanation will be given fully later. I wondered what he might have said about the report of this psychologist, who has a high standing in this field. I did not ask him, however. I did not think it worth while.
A young man of twenty who had been troubled from early life by a peculiar astigmatism was freed from it in an hour by the Bates method. He could not fuse a single one of the stereoscopic pictures when we began treatment, but he fused all of them before we stopped. The simple technique employed involved the same attentive co-operation of the vision center as was aroused in the experimental case cited above. The stage was set, however, by what I regard as an attitude of mind. His mind had been deeply impressed before he met me, by a close friend of his who had personal knowledge of cures effected by the Bates method. He had no mental reservations, and his mind responded promptly to the suggestions offered in practice during the hour.
Astigmatism is a most interesting subject. We are told that it may be hereditary or acquired. The elaborate explanations regarding its infinity of varieties, its development, its changes in conduct, the different factors which may be involved and so forth, are all very confusing, and are largely theoretical. The array of plain facts, meaning the actual experiences of those who have had it for years, are often contradictory to the imagination and the hypotheses of those who claim that the condition is not curable, and can be helped only by the use of glass lenses.
My own experience is not unusual. During thirty-seven years there was often an extreme variation in the conduct of my eyes. For months they would behave very well. Sometimes they would tire easily, become more nearsighted, receive blurred images. Those periods might last an hour or several days. Occasionally there were brief periods during which I would have astonishing optical illusions. More than once an automobile would appear to be coming toward me on my own side, although I was sure it was not. I have seen distorted images of persons and things, sections of objects missing, impossible motions. These were not delusions or hallucinations. I was perfectly aware that they were misrepresentations. The glass lenses, usually helpful, had no influence over these distortions.
One aspect is certain, and vital in relation to the treatment of such a condition. Many of the illusions were not caused by errors of refraction, and were not influenced by the artificial lenses I was wearing. The fault was in the conduct of the visual center. The treatment, therefore, must influence the mentality of the patient, and not merely modify the refraction of light rays. In my own case the proof of this is the absence of those symptoms since I have used the Bates method. There is nothing uncommon in such experiences. Witnesses on the stand, students in psychological tests, report similar aberrations of vision-and not alone those wearing glasses. In auto accidents a driver with a perfect record has declared that he simply did not see the other car, although it was right in front of him. It will not be questioned that a mental shock momentarily disturbs seriously the ordinary vision, producing the same results as are found in the condition called astigmatism. We are told in the text books that astigmatism is a common defect. But the explanations offered as causes do not begin to account for the symptoms that are in evidence. Its performances, including its frequent disappearance, temporarily or permanently, can be fully accounted for only when we consider it psychologically. The same explanation applies to most of the functional disturbances complained of by those who seek artificial lenses.
The muscular element in the mechanism of vision is certainly dominated by the nerve center. Modern medicine knows that even where changes have occurred which seem to be permanent, and where symptoms seem to indicate some change in tissue structure, the abnormal condition will sometimes revert to normal. It is a simple thing for nerve controlled muscles to cease acting in an abnormal manner when an abnormal nerve impulse is changed into a normal nerve impulse. The reactions in the nerve headquarters of the eye, the visual center, are still very much of a mystery. When they act normally, perceptions are coherent. Sometimes visual perceptions are quite incoherent. To see an object or a picture which is not present is an illusion, and is due to misconduct in the visual center, and is not to be blamed on the eye. The common, trivial illusions, with which all are familiar, are caused by some degree of dysfunction in the visual center.
When a picture becomes blurred it is probably simply an improper nerve impulse, compelling the muscles to change the shape of the eyeball, so the light rays cannot focus clearly on the retina. When the eye suddenly becomes nearsighted, or a constant nearsightedness becomes more marked or less marked for a period, the changes are caused by a different nerve impulse. When an eye crossed in one direction spontaneously changes the direction of the squint, or the squint leaves one eye and appears in the other, it cannot be denied that the muscles which held it one way have allowed a change in muscle conduct to hold it in a different way, and certainly those muscles obeyed a new nerve impulse.
All of these specific changes are in evidence, and are to be found recorded in the text books. Every one of them is either a nerve center process, or a nerve current from the center, or a muscle taking an order from a nerve. Is it not clear therefore, and absolute, that to correct these faults it is necessary to arouse the attention, and influence the conduct of the master mind in control, which is the visual center? The proof of this theory, or claim, is its success in operation, which is now a story forty years old.
The fascinating interest of these plain established facts is not simply academic. It is strange, surely, that in all the work, and all the knowledge of the specialists, this simple truth has been ignored. It is more remarkable, that in all the wonderings of the psychologists, and the experiments of the psychiatrists, this field has been neglected. What was in the mind of the psychologist who proved with his trick lenses how infinitely more the visual center can accomplish than is required by the simple effort to cure automatically as astigmatic eye? Would he say that an eye troubled with astigmatism must be resigned to the domination of a pair of glasses? The biologist who has described the intimate physiology and psychology of the body with a vividness never pictured before, puts on his glasses or lays them aside, as he talks, very much like the man with the monocle. He accepts without question the arbitrary, unfounded statements about the eyes, that have been current since first they were proposed. Some day it may occur to him to research the physiology and the psychology of the eye. It is a rich field, and of vital and practical and immediate importance to the race.