Читать книгу The Bates Method for Good Sight without Glasses - William Horatio Bates - Страница 4

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Most writers on ophthalmology appear to believe that the last word about problems of refraction (the deviation of light waves as they enter the eye) has been spoken, and according to their theories the last word is a very depressing one. Almost everyone in these days suffers from some form of refractive error. Yet we are told that for these ills, which not only are inconvenient but often are distressing and dangerous, there is no cure, no palliative except those optic crutches known as eyeglasses, and, under modern conditions of life, practically no preventive measure.

It is a well-known fact that the human body is not a perfect mechanism. Nature, in the evolution of the human tenement, has been guilty of some maladjustments. She has left behind, for instance, some troublesome bits of scaffolding, like the vermiform appendix. But nowhere is she supposed to have blundered so badly as in the construction of the eye. With one accord ophthalmologists tell us that the visual organ of man was never intended for the uses to which it is now put.

Eons before there were any schools or printing presses, electric lights or moving pictures, the evolution of the eye was complete. In those days it served the needs of the human animal perfectly. Man was a hunter, a herdsman, a farmer, a fighter. He needed, we are told, mainly distant vision; and since the eye at rest is adjusted for distant vision, sight is supposed to have been ordinarily as passive as the perception of sound, requiring no muscular action whatever. Near vision, it is assumed, was the exception, necessitating a muscular adjustment of such short duration that it was accomplished without placing any appreciable burden upon the mechanism of accommodation (the adjustment of the eye to different distances). The fact that primitive woman was a seamstress, an embroiderer, a weaver, an artist in all sorts of fine and beautiful work, appears to have been generally forgotten. Yet women living under primitive conditions have just as good eyesight as the men.

When man learned how to communicate his thoughts to others by means of written and printed forms, there came some undeniably new demands upon the eye, affecting at first only a few people but gradually including more and more, until now, in the more advanced countries, the great mass of the population is subjected to their influence. A few hundred years ago even princes were not taught to read and write. Now we compel everyone to go to school, whether he wishes to or not, and even babies are sent to kindergarten. A generation or so ago books were scarce and expensive. Today, by means of libraries of all sorts, stationary and travelling, they have been brought within the reach of almost everyone. The modern newspaper, with its endless columns of badly printed reading matter, was made possible by the discovery of the art of manufacturing paper from wood, which is a thing of yesterday. Only lately has the tallow candle been displaced by the various forms of artificial lighting, which tempt most of us to prolong our vocations and avocations into hours during which primitive man was forced to rest. Even more recently has come the moving picture to complete the supposedly destructive process.

Was it reasonable to expect that Nature should have provided for all these developments and produced an organ that could respond to the new demands? It is the accepted belief of ophthalmology today that she could not and did not, and that, while the processes of civilization depend upon the sense of sight more than upon any other, the visual organ is imperfectly fitted for its tasks.

There are a great number of facts which seem to justify this conclusion. While primitive man appears to have suffered little from defects of vision, it is safe to say that of persons over twenty-one living under civilized conditions, nine out of every ten have imperfect sight, and as the age increases the proportion increases, until at forty it is almost impossible to find a person free from visual defects. Voluminous statistics prove these assertions.

For more than a hundred years the medical profession has been seeking some method of checking the ravages of civilization upon the human eye. The Germans, to whom the matter has been one of vital military importance, have spent millions of dollars in carrying out the suggestions of experts, but without avail; and it is now admitted by most students of the subject that the methods which were once confidently advocated as reliable safeguards for the eyesight of our children have accomplished little or nothing. Some take a more cheerful view of the matter, but their conclusions are hardly borne out by the facts.

For the prevailing method of treatment, by means of artificial lenses which compensate for the refractive error of the eye, very little was ever claimed except that these contrivances neutralized the effects of the various conditions for which they were prescribed, as a crutch enables a lame man to walk. It has also been believed that they sometimes checked the progress of these conditions; but every ophthalmologist now knows that their usefulness for this purpose, if any, is very limited. In the case of myopia (short-sightedness), as long ago as 1916 some ophthalmologists realized that glasses and all ordinary methods at our command “are of but little avail” in preventing either an increase in the error of refraction or the development of the very serious complications with which it is often associated.

I have been studying the refraction of the human eye for more than thirty years, and my observations fully confirm these conclusions as to the uselessness of all the methods heretofore employed for the prevention and treatment of errors of refraction. I was very early led to suspect, however, that the problem was by no means an unsolvable one.

Every ophthalmologist of any experience knows that the theory of the incurability of errors of refraction does not fit the observed facts. Not infrequently such cases recover spontaneously, or change from one form to another. It has long been the custom either to ignore these troublesome facts or to explain them away, and fortunately for those who consider it necessary to bolster up the old theories at all costs, the role attributed to the lens of the eye in accommodation offers, in the majority of cases, a plausible method of explanation.

According to this theory, which most of us learned at school, the eye changes its focus for vision at different distances by altering the curvature of the lens; and in seeking an explanation for the inconstancy of the theoretically constant error of refraction, the theorists hit upon the very ingenious idea of attributing to the lens a capacity for changing its curvature not only for the purpose of normal accommodation but also to cover up or to produce accommodative errors. In hypermetropia (commonly but improperly called far-sightedness, although the patient with such a defect can see clearly neither at the distance nor at the near-point) the eyeball is too short from the front to the back, and all rays of light, both the convergent ones coming from near objects and the parallel ones coming from distant objects, are focused behind the retina instead of upon it. In myopia it is too long from the front to the back, and while the divergent rays from near objects come to a point upon the retina, the parallel ones from distant objects do not reach it.

Both of these conditions are supposed to be permanent, the one congenital, the other acquired. Thus when persons who at one time appear to have hypermetropia or myopia appear at other times not to have them, or to have them in lesser degrees, it is not permissible to suppose that there has been a change in the shape of the eyeball. Therefore, in the case of the disappearance or lessening of hypermetropia, we are asked to believe that the eye, in the act of vision, both at the near-point and at the distance, increases the curvature of the lens sufficiently to compensate, in whole or in part, for the flatness of the eyeball. In myopia, on the contrary, we are told that the eye actually goes out of its way to produce the condition, or to make an existing condition worse. In other words, the so-called “ciliary muscle”, believed to control the shape of the lens, is credited with a capacity for getting into a more or less continuous state of contraction, thus keeping the lens continuously in a state of convexity which, according to the theory, it ought to assume only for vision at the near-point.

These curious performances may seem unnatural to the lay mind, but ophthalmologists believe the tendency to indulge in them to be so ingrained in the constitution of the organ of vision that, in the fitting of glasses, it is customary to instil atropine—the “drops” with which everyone who has visited an oculist is familiar—into the eye, for the purpose of paralysing the ciliary muscle and thus, by preventing any change of curvature in the lens, bringing out “latent hypermetropia” and getting rid of “apparent myopia”.

The interference of the lens, however, is believed to account for only moderate degrees of variation in errors of refraction, and that only during the earlier years of life. For the higher ones, or those that occur after forty-five years of age, when the lens is supposed to have lost its elasticity to a greater or lesser degree, no plausible explanation has ever been found.

The disappearance of astigmatism, or changes in its character, present an even more baffling problem. This condition is due in most cases to an unsymmetrical change in the curvature of the cornea, resulting in failure to bring the light rays to a focus at any point, and the eye is supposed to possess only a limited ability to overcome it—and yet astigmatism comes and goes with as much facility as other errors of refraction. It is well known, too, that it can be produced voluntarily. Some persons can produce as much as three dioptres (a dioptre is the focusing power necessary to bring parallel rays to a focus at one metre, or 39.37 inches). I myself can produce one and a half.

Examining thousands of pairs of eyes a year at the New York Eye and Ear Infirmary and other institutions, I observed many cases in which errors of refraction either recovered spontaneously or changed their form, and I was unable either to ignore them or to satisfy myself with the orthodox explanations, even where such explanations were available. It seemed to me that if a statement is a truth it must always be a truth. There can be no exceptions. If errors of refraction are incurable, they should not recover, or change their form, spontaneously.

In the course of time I discovered that myopia and hypermetropia, like astigmatism, could be produced at will; that myopia was not, as we have so long believed, associated with the use of the eyes at the near-point, but with a strain to see distant objects, strain at the near-point being associated with hypermetropia; that no error of refraction was ever a constant condition; and that the lower degrees of refractive error could be eliminated, while higher degrees could be improved.

In seeking light upon these problems I examined tens of thousands of eyes, and the more facts I accumulated, the more difficult it became to reconcile them with the accepted views. Finally I undertook a series of observations upon the eyes of human beings and the lower animals, the results of which convinced both myself and others that the lens is not a factor in accommodation and that the adjustment necessary for vision at different distances is affected in the eye, precisely as it is in the camera, by a change in the length of the organ, this alteration being brought about by the action of the muscles on the outside of the eyeball. Equally convincing was the demonstration that errors of refraction, including presbyopia (rigidity of the lens, causing difficulty in accommodation and recession of the near-point), are due not to an organic change in the shape of the eyeball or in the constitution of the lens, but to a functional derangement in the action of the muscles on the outside of the eyeball, and therefore can be eliminated.

In making these statements I am well aware that I am controverting the practically undisputed teaching of ophthalmological science for the better part of a century, but I have been driven to my conclusions by the facts, and so slowly that I am now surprised at my own hesitation. At the time I was improving high degrees of myopia, but I wanted to be conservative and I differentiated between functional myopia, which I was able to eliminate or improve, and organic myopia, which, in deference to the orthodox tradition, for a time I accepted as incorrigible.