When the mind is able to remember perfectly any phenomenon of the senses, it is always perfectly relaxed. The sight is normal, if the eyes are open; and when they are closed and covered so as to exclude all the light, one sees a perfectly black field – that is nothing at all. If you can remember the ticking of a watch, or an odor or a taste perfectly, your mind is perfectly at rest, and you will see a perfect black when your eyes are closed and covered. If your memory of a sensation of touch could be equal to the reality, you would see nothing but black when the light was excluded from your eyes. If you were to remember a bar of music perfectly when your eyes were closed and covered, you would see nothing but black. But in the case of any of these phenomena it is not easy to test the correctness of the memory, and the same is true of colors other than black. All other colors, including white, are altered by the amount of light to which they are exposed, and are seldom seen as perfectly as it is possible for the normal eye to see them. But when the sight is normal, black is just as black in a dim light as in a bright one. It is also just as black at the distance as at the near-point, while a small area is just as black as a large one, and, in fact, appears blacker. Black is, moreover, more readily available than any other color. There is nothing blacker than printer’s ink, and that is practically ubiquitous. By means of the memory of black, therefore, it is possible to measure accurately one’s own relaxation. If the color is remembered perfectly, one is perfectly relaxed. If it is remembered almost perfectly, one’s relaxation is almost perfect. If it cannot be remembered at all, one has very little or no relaxation.
By means of simultaneous retinoscopy, these facts can be readily demonstrated. An absolutely perfect memory is very rare, so much so that it need hardly be taken into consideration; but a practically perfect memory, or what might be called normal, is attainable by every one under certain conditions. With such a memory of black, the retinoscope shows that all errors of refraction are corrected. If the memory is less than normal, the contrary will be the case. If it fluctuates, the shadow of the retinoscope will fluctuate. The testimony of the retinoscope is, in fact, more reliable than the statements of the patient. Patients often believe and state that they remember black perfectly, or normally, when the retinoscope indicates an error of refraction; but in such cases it can usually be demonstrated by bringing the test card to the point at which the black letters can be seen best, that the memory is not equal to the sight. That the color cannot be remembered perfectly when the eyes and mind are under a strain, the reader can easily demonstrate by trying to remember it when making a conscious effort to see – by staring, partly closing the eyes, frowning, etc – or while trying to see all the letters of a line equally well at one time. It will be found that it either cannot be remembered at all under these conditions, or that it is remembered very imperfectly.
When the two eyes of a patient are different, it has been found that the difference can be exactly measured by the length of time a black period can be remembered, while looking at the Snellen test card, with both eyes open, and with the better eye closed. A patient with normal vision in the right eye and half-normal vision in the left could, when looking at the test card with both eyes open, remember a period for twenty seconds continuously; but with the better eye closed, it could be remembered only ten seconds. A patient with half-normal vision in the right eye and one-quarter normal in the left could remember a period twelve seconds with both eyes open, and only six seconds with the better eye closed. A third patient, with normal sight in the right eye and vision of one-tenth in the left, could remember a period twenty seconds with both eyes open, and only two seconds when the better eye was closed. In other words, if the right eye is better than the left, the memory is better when the right eye is open than when only the left eye is open, the difference being in exact proportion to the difference in the vision of the two eyes.
In the treatment of functional eye troubles this relationship between relaxation and memory is of great practical importance. The sensations of the eye and of the mind supply very little information as to the strain to which both are being subjected, those who strain most often suffering the least discomfort; but by means of his ability to remember black the patient can always know whether he is straining or not, and is able, therefore, to avoid the conditions that produce strain. Whatever method of improving his sight the patient is using, he is advised to carry with him constantly the memory of a small area of black, such as a period, so that he may recognize and avoid the conditions that produce strain, and in some cases patients have obtained a complete cure in a very short time by this means alone. One advantage of the method is that it does not require a test card, for at any hour of the day or night, whatever the patient may be doing, he can always place himself in the conditions favorable to the perfect memory of a period.
The condition of mind in which a black period can be remembered cannot be attained by any sort of effort. The memory is not the cause of the relaxation, but must be preceded by it. It is obtained only during moments of relaxation, and retained only as long as the causes of strain are avoided; but how this is accomplished cannot be fully explained, just as many other psychological phenomena cannot be explained. We only know that under certain conditions that might be called favorable a degree of relaxation sufficient for the memory of a black period is possible, and that, by persistently seeking these conditions, the patient becomes able to increase the degree of the relaxation and prolong its duration, and finally becomes able to retain it under unfavorable conditions.
For most patients palming provides the most favorable conditions for the memory of black. When the strain to see is lessened by the exclusion of the light, the patient usually becomes able to remember a black object for a few seconds or longer, and this period of relaxation can be prolonged in one of two ways. Either the patient can open his eyes and look at a black object by central fixation at the distance at which it can be seen best, and at which the eyes are, therefore, most relaxed, or he can shift mentally from one black object to another, or from one part of a black object to another. By these means, and perhaps also through other influences that are not clearly understood, most patients become able, sooner or later, to remember black for an indefinite length of time with their eyes closed and covered.
With the eyes open and looking at a blank surface without trying consciously to see, the unconscious strain is lessened so that the patient becomes able to remember a black period, and all errors of refraction, as demonstrated by the retinoscope, are corrected. This result has been found to be invariable, and so long as the surface remains blank and the patient does not begin to remember or imagine things seen imperfectly, the memory and the vision may be retained. But if, with the improved vision, details upon the surface begin to come out, or if the patient begins to think of the test card, which he has seen imperfectly, the strain to see will return and the period will be lost.
When looking at a surface on which there is nothing particular to see, distance makes no difference to the memory, because the patient can always look at such a surface, no matter where it is, without straining to see it. When looking at letters, or other details, however, the memory is best at the point at which the patient’s sight is best, because at that point the eyes and mind are more relaxed than when the same letters or objects are regarded at distances at which the vision is not so good. By practicing central fixation at the most favorable distance, therefore, and using any other means of improving the vision which are found effectual, the memory of the period may be improved, in some cases, very rapidly.
If the relaxation gained under these favorable conditions is perfect, the patient will be able to retain it when the mind is conscious of the impressions of sight at unfavorable distances. Such cases are, however, very rare. Usually the degree of relaxation gained is markedly imperfect, and is, therefore, lost to a greater or less degree when the conditions are unfavorable, as when letters or objects are being regarded at unfavorable distances. So disturbing are the impressions of sight under these circumstances, that just as soon as details begin to come out at distances at which they have not previously been seen, the patient usually loses his relaxation, and with it the memory of the period. In fact, the strain to see may even return before he has had time to become conscious of the image on his retina, as the following case strikingly illustrates:
A woman of fifty-five who had myopia of fifteen diopters, complicated with other conditions which made it impossible for her to see the big C at more than one foot, or to go about, either in her house or on the street, without an attendant, became able, when she looked at a green wall without trying to see it, to remember a perfectly black period and to see a small area of the wall-paper at the distance as well as she could at the near-point. When she had come close to the wall, she was asked to put her hand on the door-knob, which she did without hesitation. “But I don’t see the knob,” she hastened to explain. As a matter of fact she had seen it long enough to put her hand on it; but as soon as the idea of seeing it was suggested to her she lost the memory of the period, and with it her improved vision, and when she again tried to find the knob she could not do so.
When a period is remembered perfectly while a letter on the Snellen test card is being regarded, the letter improves, with or without the consciousness of the patient; because it is impossible to strain and relax at the same time, and if one relaxes sufficiently to remember the period, one must also relax sufficiently to see the letter, consciously or unconsciously. Letters on either side of the one regarded, or on the lines above and below it, also improve. When the patient is conscious of seeing the letters, this is very distracting, and usually causes him, at first, to forget the period; while with some patients, as already noted the strain may return even before the letters are consciously recognized.
Thus patients find themselves on the horns of a dilemma. The relaxation indicated by the memory of a period improves their sight, and the things they see with this improved vision cause them to lose their relaxation and their memory. It is very remarkable to me how the difficulty is ever overcome, but some patients are able to do it in five minutes or half an hour. With others the process is long and tedious.
There are various ways of helping patients to deal with this situation. One is to direct them to remember the period while looking a little to one side of the test card, say a foot or more; then to look a little nearer to it, and finally to look between the lines. In this way they may become able to see the letters in the eccentric field without losing the period; and when they can do this they may become able to go a step farther, and look directly at a letter without losing control of their memory. If they cannot do it, they are told to look at only one part of a letter – usually the bottom – or to see or imagine the period as part of the letter, while noting that the rest of the letter is less black and less distinct than the part directly regarded- When they can do this they become able to remember the period better than when the letter is seen all alike. If the letter is seen all alike, the perfect memory of the period is always lost. The next step is to ask the patient to note whether the bottom of the letter is straight, curved, or open, without losing the period on the bottom. When he can do this, he is asked to do the same with the sides and top of the letter, still holding the period on the bottom. Usually when the parts can be observed separately in this way, the whole letter can be seen without losing the memory of the period; but it occasionally happens that this is not the case, and further practice is needed before the patient can become conscious of all sides of the letter at once without losing the period. This may require moments, hours, days, or months. In one case the following method succeeded:
The patient, a man with fifteen diopters of myopia, was so much disturbed by what he saw when his vision had been improved by the memory of a period that he was directed to look away from the Snellen test card, or whatever object he was regarding, when he found the letters or other details coming out; and for about a week he went around persistently dodging his improved sight. As his memory improved, it became more and more difficult for him to do this, and at the end of the week it was impossible. When he looked at the bottom line at a distance of twenty feet he remembered the period perfectly, and when asked if he could see the letters, he replied:
“I cannot help but see them.”
Some patients retard their recovery by decorating the scenery with periods as they go about during the day, instead of simply remembering a period in their minds. This does them no good, but is, on the contrary, a cause of strain. The period can be imagined perfectly and with benefit as forming part of a black letter on the test card, because this merely means imagining that one sees one part of the black letter best; but it cannot be imagined perfectly on any surface which is not black, and to attempt to imagine it on such surfaces defeats the end in view.
The smaller the area of black which the patient is able to remember, the greater is the degree of relaxation indicated; but some patients find it easier, at first, to remember a somewhat larger area, such as one of the letters on the Snellen test card with one part blacker than the rest. They may begin with the big C, then proceed to the smaller letters, and finally get to a period. It is then found that this small area is remembered more easily than the larger ones, and that its black is more intense. Instead of a period, some patients find it easier to remember a colon, with one period blacker than the other, or a collection of periods, with one blacker than all the others, or the dot over an i or j. Others, again, prefer a comma to a period. In the beginning most patients find it helpful to shift consciously from one of these black areas to another, or from one part of such an area to another, and to realize the swing, or pulsation, produced by such shifting (see Chapter XV); but when the memory becomes perfect, one object may be held continuously, without conscious shifting, while the swing is realized only when attention is directed to the matter.
Although black is, as a rule, the best color to remember, some patients are bored or depressed by it, and prefer to remember white or some other color. A familiar object, or one with pleasant associations, is often easier to remember than one which has no particular interest. One patient was cured by the memory of a yellow buttercup, and another was able to remember the opal of her ring when she could not remember a period. Whatever the patient finds easiest to remember is the best to remember, because the memory can never be perfect unless it is easy.
When the memory of the period becomes habitual, it is not only not a burden, but is a great help to other mental processes. The mind, when it remembers one thing better than all other things, possesses central fixation, and its efficiency is thereby increased, just as the efficiency of the eye is increased by central fixation. In other words, the mind attains its greatest efficiency when it is at rest, and it is never at rest unless one thing is remembered better than all other things. When the mind is in such a condition that a period is remembered perfectly, the memory for other things is improved.
A high-school girl reports that when she was unable to remember the answer to a question in an examination, she remembered the period, and the answer came to her. When I cannot remember the name of a patient, I remember a period – and, behold, I have it! A musician who had perfect sight and could remember a period perfectly, had a perfect memory for music; but a musician with imperfect sight who could not remember a period could play nothing without his notes, only gaining that power when his sight and visual memory had become normal. In some exceptional cases, the strain to see letters on the Snellen test card has been so terrific that patients have said that they not only could not remember a period while they were looking at them, but could not remember even their own names.
Patients may measure the accuracy of their memory of the period, not only by comparing it with the sight, but by the following tests:
When the memory of the period is perfect it is instantaneous. If a few seconds or longer are necessary to obtain the memory, it is never perfect.
A perfect memory is not only instantaneous, but continuous.
When the period is remembered perfectly perfect sight comes instantaneously. If good vision is obtained only after a second or two, it can always be demonstrated that the memory of the period is imperfect and the sight also.
The memory of a period is a test of relaxation. It is the evidence by which the patient knows that his eyes and mind are at rest. It may be compared to the steam-gauge of an engine, which has nothing to do with the machinery, but is of great importance in giving information as to the ability of the mechanism to do its work. When the period is black one knows that the engine of the eye is in good working order. When the period fades, or is lost, one knows that it is out of order, until a cure is effected. Then one does not need a period, or any other aid to vision, just as the engineer does not need a steam-gauge when the engine is going properly. One patient who had gained telescopic and microscopic vision by the methods presented in this book said, in answer to an inquiry from some one interested in investigating the treatment of errors of refraction without glasses, that he had not only done nothing to prevent a relapse, but had even forgotten how he was cured. The reply was unsatisfactory to the inquirer, but is quoted to illustrate the fact that when a patient is cured he does not need to do anything consciously in order to stay cured, although the treatment can always be continued with benefit, since even supernormal vision can be improved.