Among people living under civilized conditions the accommodative power of the eye gradually declines, in most cases, until at the age of sixty or seventy it appears to have been entirely lost, the subject being absolutely dependent upon his glasses for vision at the near-point. As to whether the same thing happens among primitive people or people living under primitive conditions, very little information is available. Donders (1) says that the power of accommodation diminishes little, if at all, more rapidly among people who use their eyes much at the near-point than among agriculturists, sailors and others who use them mainly for distant vision; and Roosa and others(2) say the contrary. This is a fact however, that people who cannot read, no matter what their age, will manifest a failure of near vision if asked to look at printed characters, although their sight for familiar objects at the near-point may be perfect. The fact that such persons, at the age of forty-five or fifty, cannot differentiate between printed characters is no warrant, therefore, for the conclusion that their accommodative powers are declining. A young illiterate would do no better, and a young student who can read Roman characters at the near-point without difficulty always develops symptoms of imperfect sight when he attempts to read, for the first time, old English, Greek, or Chinese characters.
When the accommodative power has declined to the point at which reading and writing become difficult the patient is said to have “presbyopia,” or, more popularly, “old sight”; and the condition is generally accepted, both by the popular and the scientific mind, as one of the unavoidable inconveniences of old age. “Presbyopia,” says Donders, “is the normal quality of the normal, emmetropic eye in advanced age(3),” and similar statements might be multiplied endlessly. De Schweinitz calls the condition “a normal result of growing old”;(4) according to Fuchs it is “a physiological process which every eye undergoes”;(5) while Roosa speaks of the change as one which “ultimately affects every eye.”(6)
The decline of accommodative power with advancing years is commonly attributed to the hardening of the lens, an influence which is believed to be augmented, in later years, by a flattening of this body and a lowering of its refractive index, together with weakness or atrophy of the ciliary muscle; and so regular is the decline, in most cases, that tables have been compiled showing the near-point to be expected at various ages. From these it is said one might almost fit glasses without testing the vision of the subject; or, conversely, one might, from a man’s glasses, judge his age within a year or two. The following table is quoted from Jackson’s chapter on “The Dioptrics of the Eye,” in Norris and Oliver’s “System of Diseases of the Eye,” (7) and does not differ materially from the tables given by Fuchs, Donders and Duane. The first column indicates the age, the second diopters of accommodative power, the third the near-point for an emmetropic (8) eye, in inches.
According to these depressing figures one must expect at thirty to have lost no less than half of one’s original accommodative power, while at forty two-thirds of it would be gone, and at sixty it would be practically nonexistent.
There are many people, however, who do not fit this schedule. Many persons at forty can read fine print at four inches, although they ought, according to the table, to have lost that power shortly after twenty. Worse still, there are people who refuse to become presbyopic at all. Oliver Wendell Holmes mentions one of these cases in “The Autocrat of the Breakfast Table.”
“There is now living in New York State,” he says, “an old gentleman who, perceiving his sight to fail, immediately took to exercising it on the finest print, and in this way fairly bullied Nature out of her foolish habit of taking liberties at five-and-forty, or thereabout. And now this old gentleman performs the most extraordinary feats with his pen, showing that his eyes must be a pair of microscopes. I should be afraid to say how much he writes in the compass of a half-dime – whether the Psalms or the Gospels, or the Psalms and the Gospels, I won’t be positive.”(9)
There are also people who regain their near vision after having lost it for ten, fifteen, or more years; and there are people who, while presbyopic for some objects, have perfect sight for others. Many dressmakers, for instance, can thread a needle with the naked eye, and with the retinoscope it can be demonstrated that they accurately focus their eyes upon such objects; and yet they cannot read or write without glasses.
So far as I am aware no one but myself has ever observed the last-mentioned class of cases, but the others are known to every ophthalmologist of any experience. One hears of them at the meetings of ophthalmological societies; they are even reported in the medical journals; but such is the force of authority that when it comes to writing books they are either ignored or explained away, and every new treatise that comes from the press repeats the old superstition that presbyopia is “a normal result of growing old.” We have beaten Germany; but the dead hand of German science still oppresses our intellects and prevents us from crediting the plainest evidence of our senses. Some of us are so filled with repugnance for the Hun that we can no longer endure the music of Bach, or the language of Goethe and Schiller; but German ophthalmology is still sacred, and no facts are allowed to cast discredit upon it.
Fortunately for those who feel called upon to defend the old theories, myopia postpones the advent of presbyopia. and a decrease in the size of the pupil, which often takes place in old age, has some effect in facilitating vision at the near-point. Reported cases of persons reading without glasses when over fifty or fifty-five years of age, therefore, can be easily disposed of by assuming that the subjects must be myopic, or that their pupils are unusually small. If the case comes under actual observation, the matter may not be so simple, because it may be found that the patient, so far from being myopic, is hypermetropic, or emmetropic, and that the pupil is of normal size. There is nothing to da with these cases but to ignore them. Abnormal changes in the form of the lens have also been held responsible for the retention of near vision beyond the prescribed age, or for its restoration after it has been lost, the swelling of the lens in incipient cataract affording a very convenient and plausible explanation for the latter class of cases. In cases of premature presbyopia “accelerated sclerosis” (10) Of the lens and weakness of the ciliary muscle have been assumed; and if such cases as the dressmakers who can thread their needles when they can no longer read the newspapers had been observed, no doubt some explanation consistent with the German viewpoint would have been found for them.
The truth about presbyopia is that it is not “a normal result of growing old,” being both preventable and curable. It is not caused by hardening of the lens, but by a strain to see at the near-point. It has no necessary connection with age, since it occurs, in some cases, as early as ten years, while in others it never occurs at all, although the subject may live far into the so-called presbyopic age. It is true that the lens does harden with advancing years, just as the bones harden and the structure of the skin changes; but since the lens is not a factor in accommodation, this fact is immaterial, and while in some cases the lens may become flatter, or lose some of its refractive power with advancing years, it has been observed to remain perfectly clear and unchanged in shape up to the age of ninety. Since the ciliary muscle is also not a factor in accommodation, its weakness or atrophy can contribute nothing to the decline of accommodative power. Presbyopia is, in fact, simply a form of hypermetropia in which the vision for the near-point is chiefly affected, although the vision for the distance, contrary to what is generally believed, is always lowered also. The difference between the two conditions is not always clear. A person with hypermetropia may or may not read fine print, and a person at the presbyopic age may read it without apparent inconvenience and yet have imperfect sight for the distance. In both conditions the sight at both points is lowered, although the patient may not be aware of it.
It has been shown that when the eyes strain to see at the near-point the focus is always pushed farther away than it was before, in one or all meridians; and by means of simultaneous retinoscopy it can always be demonstrated that when a person with presbyopia tries to read fine print and fails, the focus is always pushed farther away than it was before the attempt was made, indicating that the failure was caused by strain. Even the thought of making such an effort will produce strain, so that the refraction may be changed, and pain, discomfort and fatigue produced, before the fine print is regarded. Furthermore, when a person with presbyopia rests the eyes by closing them, or palming, he always becomes able, for a few moments at least, to read fine print at six inches, again indicating that his previous failure was due, not to any fault of the eyes, but to a strain to see. When the strain is permanently relieved the presbyopia is permanently cured, and this has happened, not in a few cases, but in many, and at all ages, up to sixty, seventy and eighty.
The first patient that I cured of presbyopia was myself. Having demonstrated by means of experiments on the eyes of animals that the lens is not a factor in accommodation, I knew that presbyopia must be curable, and I realized that I could not look for any very general acceptance of the revolutionary conclusions I had reached so long as I wore glasses myself for a condition supposed to be due to the loss of the accommodative power of the lens. I was then suffering from the maximum degree of presbyopia. I had no accommodative power whatever, and had to have quite an outfit of glasses, because with a glass, for instance, which enabled me to read fine print at thirteen inches, I could not read it either at twelve inches or at fourteen. The retinoscope showed that when I tried to see anything at the near-point without glasses my eyes were focussed for the distance, and when I tried to see anything at the distance they were focussed for the near-point. My problem, then, was to find some way of reversing this condition and inducing my eyes to focus for the point I wished to see at the moment that I wished to see it. I consulted various eye specialists, but my language was to them like that of St. Paul to the Greeks, namely, foolishness. “Your lens is as hard as a stone,” they said. “No one can do anything for you.” Then I went to a nerve specialist. He used the retinoscope on me, and confirmed my own observations as to the peculiar contrariness of my accommodation; but he had no idea what I could do about it. He would consult some of his colleagues, he said, and asked me to come back in a month, which I did. Then he told me he had come to the conclusion that there was only one man who could cure me, and that was Dr. William H. Bates of New York.
“Why do you say that?” I asked.
“Because you are the only man who seems to know anything about it,” he answered.
Thus thrown upon my own resources, I was fortunate enough to find a non-medical gentleman who was willing to do what he could to assist me, the Rev. R. B. B. Foote, of Brooklyn. He kindly used the retinoscope through many long and tedious hours while I studied my own case, and tried to find some way of accommodating when I wanted to read, instead of when I wanted to see something at the distance. One day, while looking at a picture of the Rock of Gibraltar which hung on the wall, I noted some black spots on its face. I imagined that these spots were the openings of caves, and that there were people in these caves moving about. When I did this my eyes were focussed for the reading distance. Then I looked at the same picture at the reading distance, still imagining that the spots were caves with people in them. The retinoscope showed that I had accommodated, and I was able to read the lettering beside the picture. I had, in fact, been temporarily cured by the use of my imagination. Later I found that when I imagined the letters black I was able to see them black, and when I saw them black I was able to distinguish their form. My progress after this was not what could be called rapid. It was six months before I could read the newspapers with any kind of comfort, and a year before I obtained my present accommodative range of fourteen inches, from four inches to eighteen; but the experience was extremely valuable, for I had in pronounced form every symptom subsequently observed in other presbyopic patients.
Fortunately for the patients, it has seldom taken me as long to cure other people as it did to cure myself. In some cases a complete and permanent cure was effected in a few minutes. Why, I do not know. I will never be satisfied till I find out. A patient who had worn glasses for presbyopia for about twenty years was cured in less than fifteen minutes by the use of his imagination.
When asked to read diamond type, he said he could not do so, because the letters were grey and looked all alike. I reminded him that the type was printer’s ink and that there was nothing blacker than printer’s ink. I asked him if he had ever seen printer’s ink. He replied that he had. Did he remember how black it was? Yes. Did he believe that these letters were as black as the ink he remembered? He did, and then he read the letters; and because the improvement in his vision was permanent, he said that I had hypnotized him.
In another case a presbyope of ten years’ standing was cured just as quickly by the same method. When reminded that the letters which he could not read were black, he replied that he knew they were black, but that they looked grey.
“If you know they are black, and yet see them grey,” I said, “you must imagine them grey. Suppose you imagine that they are black. Can you do that ?”
“Yes,” he said, “I can imagine that they are black”; and then he proceeded to read them.
These extremely quick cures are rare. In nine cases out of ten progress has been much slower, and it has been necessary to resort to all the methods of obtaining relaxation found useful in the treatment of other errors of refraction. In the more difficult cases of presbyopia the patients often suffer from the same illusions of color, size, form and number, when they try to read fine print, as do patients with hypermetropia, astigmatism, and myopia when they try to read the letters on the Snellen test card at the distance. They are unable to remember or imagine, when trying to see at the near-point, even such a simple thing as a small black spot, but can remember it perfectly when they do not try to see. Their sight for the distance is often very imperfect and always below normal, although they may have thought it perfect; and just as in the case of other errors of refraction, improvement of the distant vision improves the vision at the near-point. Regardless, however, of the difficulty of the case and the age of the patient; some improvement has always been obtained, and if the treatment was continued long enough, the patient has been cured.
The idea that presbyopia is “a normal result of growing old” is responsible for much defective eyesight. When people who have reached the presbyopic age experience difficulty in reading, they are very likely to resort at once to glasses, either with or without professional advice. In some cases such persons may be actually presbyopic; in others the difficulty may be something temporary, which they would have thought little about if they had been younger, and which would have passed away if Nature had been left to herself. But once the glasses are adopted, in the great majority of cases, they produce the condition they were designed to relieve, or, if it already existed, they make it worse, sometimes very rapidly, as every ophthalmologist knows. In a couple of weeks sometimes, the patient finds, as noted in the chapter on What Glasses Do to Us, that the large print which he could read without difficulty before
he got his glasses, can no longer be read without their aid. In from five to ten years the accommodative power of the eye is usually gone; and if from this point the patient does not go on to cataract, glaucoma, or inflammation of the retina, he may consider himself fortunate. Only occasionally do the eyes refuse to submit to the artificial conditions imposed upon them; but in such cases they may keep up an astonishing struggle against them for long periods. A woman of seventy, who had worn glasses for twenty years, was still able to read diamond type and had good vision for the distance without them. She said the glasses tired her eyes and blurred her vision, but that she had persisted in wearing them, in spite of a continual temptation to throw them off, because she had been told that it was necessary for her to do so.
If persons who find themselves getting presbyopic, or who have arrived at the presbyopic age, would, instead of resorting to glasses, follow the example of the gentleman mentioned by Dr. Holmes, and make a practice of reading the finest print they can find, the idea that the decline of accommodative power is “a normal result of growing old” would soon die a natural death.
1. On the Anomalies of Accommodation and Refraction of the Eye, p. 223.
2. Roosa: A Clinical Manual of Diseases of the Eye, 1894, p. 537; Oliver: System of Diseases of the Eye, vol. iv, p, 431.
3. On the Anomalies of Accommodation and Refraction of the Eye, p. 210.
4. Diseases of the Eye, p. 148.
5. Text-book of Ophthalmology, authorized translation from the twelfth German edition by Duane, 1919, p. 862. Ernst Fuchs (1851- ). Professor of Ophthalmology at Vienna from 1885 to 1915. His Text-book of Ophthalmology has been translated into many languages.
6. A Clinical Manual of Diseases of the Eye, p. 535.
7. Vol. i, p. 504.
8. An eye which, when it is at rest, focusses parallel rays upon the retina, is said to be emmetropic or normal.
9. Everyman’s Library, 1908, pp. 166-167.
10. Fuchs: Text-book of Ophthalmology, p. S05.