Myopia

“ The fact is that it sometimes produces myopia, or changes hypermetropia into myopia, and that it will produce both myopia and hypermetropia in persons over seventy years of age, when the lens is supposed to be as hard as a stone, as well as in cases in which the lens is hard with incipient cataract. Patients with eyes apparently normal will, after the use of atropine, develop hypermetropic astigmatism, or myopic astigmatism, or compound myopic astigmatism, or mixed astigmatism.2 In other cases the drug will not interfere with the accommodation, or alter the refraction in any way. ”

“ Those which pass over the white figure follow the abnormal curvature of the tunics; they appear to bend forwards towards the vitreous chamber, where they pass from the "white" on to the "red" portion of the figure.
Fig. 22.
Myopia. Right eye of a person with brown irides.
The optic disc with a small portion of the retina, choroid, and sclerotic adjoining it.
The optic disc has a pink colour, and appears oval-shaped, with the long axis of the oval vertical. The white figure which surrounds the optic disc has not a crescentic but an irregular shape, as is often observed in extreme myopia. ”

“ When fine print can be read under adverse conditions, the reading of ordinary print under ordinary conditions is vastly improved. In myopia it may be a benefit to strain to see fine print, because myopia is always lessened when there is a strain to see near objects, and this has sometimes counteracted the tendency to strain in looking at distant objects, which is always associated with the production of myopia. Even straining to see print so fine that it cannot be read is a benefit to some myopes.
Persons who wish to preserve their eyesight are frequently warned not to read in moving vehicles ”

“ THE PREVENTION AND CURE OF MYOPIA AND OTHER ERRORS OF REFRACTION A Method That Succeeded
You cannot see anything with perfect sight unless you have seen it before. When the eye looks at an unfamiliar object it always strains more or less to see that object, and an error of refraction is always produced. When children look at unfamiliar writing, or figures, on the blackboard, distant maps, diagrams, or pictures, the retinoscope always shows that they are myopic, though their vision may be under other circumstances absolutely normal. ”

“ It appears that emmetropia—which the authors regard as synonymous with normal vision, though there are good grounds for regarding the hypermetropic eye as normal—actually increases, from the age of six to ten, while astigmatism decreases. There is no appreciable change in myopia. Myopia, or near-sightedness, does increase from the age of ten to fourteen, though only to 6.5 per cent, of the children. ”

“ Nature always compensates in some way. I grant that the present demands of civilization could not be filled by the far sighted eye, but the evil which is the outgrowth of present demands does not stop when we have reached the normal eye, but the cause once excited, the coats of this eye continue to give way, and myopia or a near sighted condition is the result.
Among three hundred Indians examined, I found when I got to the Creeks, a tribe which has been semi-civilized for many years, myopia to be the prevailing visual defect. ”

“ The patient with progressive myopia whose case was mentioned in Chapter XV returned after her cure to the specialist who had prescribed her glasses, and who had said not only that there was no hope of improvement, but that the condition would probably progress until it ended in blindness, to tell him the good news which, as an old friend of her family, she felt he had a right to hear. But while he was unable to deny that her vision was, in fact, normal without glasses, he said it was impossible that she should have been cured of myopia, because myopia was incurable. ”

“ When, therefore, 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. ”

“ If investigators similarly work out all the other correlations that can be suggested, finding [Pg 13] whether there is any regular relation between myopia and overcrowding, long hours of study, general economic conditions at home, general physical or moral conditions of parents, the time the child spends out of doors, etc., and if no important relation is found between these various factors and myopia, it will be evident that no factor of the environment which one can think of as likely to cause the trouble really accounts for the poor eyesight of school children. ”

“ If Nature has attempted to adapt the eye to civilized conditions by an elongation of the globe, she has done it in a very clumsy manner. It is true that many authorities assume the existence of two kinds of myopia, one physiological, or at least harmless, and the other pathological ”

“ 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. ”

“ It has also been found that there is just as much myopia in schools where little near work is done as in those in which the demands upon the accommodative power of the eye are greater, while in any case it is only a minority of the children in any school who become myopic, although all may be exposed to practically the same eye conditions. ”

“ A small amount of myopia, if it is stationary, is in no sense a serious defect of the eye, the possessors of it are often quite unconscious of any deficiency in vision, and in fact brag that they have better vision than their fellows. The reason of this is that they learn in early life to recognize indistinct distant objects by the aid of other senses in a way that the ordinary individual can hardly understand, and in later life they can postpone the wearing of glasses for near work for many years, and sometimes until extreme old age. ”

“ The muscles of accommodation are thus relieved of their extra work.
“Short sight,” known as myopia, is one of the commonest defects of vision. In this defect the axis of the eye, or the distance between the cornea and the retina, is too long and the rays of light are brought to a focus in front of the retina. The tendency to short-sightedness exists in many cases at birth, and is largely hereditary. It is alarmingly common with those who make a severe demand upon the eyes. During childhood there is a marked increase of near-sightedness. ”

“ A fortnight after the operation, on correction of the myopia, patient could see singly to 3 mtr.: towards both sides homonymous double images were still present, and in fixation to 30 cm. relative divergence on exclusion of one eye. Six months after the operation, on correction of the myopia and application of red glass to one eye, crossed double images occur close together, which become homonymous by means of a prism of 3° with the base inwards. Patient sees double images always, without being much disturbed by them, yet they cannot be united by means of prisms. ”

“ A person with myopia of 20/70 who puts on glasses giving him a vision of 20/20 may find that in a week's time his unaided vision has declined to 20/200, and we have the testimony of Dr. Sidler-Huguenin, of Zurich,1 that of the thousands of myopes treated by him the majority grew steadily worse, in spite of all the skill he could apply to the fitting of glasses for them. When people break their glasses and go without them for a week or two, they frequently observe that their sight has improved. ”

“ Asthenopic disturbances are certainly frequent in myopia, but the above method of inquiry does not at all prove that their cause lies in the ocular muscles, for those appearances from which one concludes dynamic relative divergence and muscular asthenopia, are found in almost all myopes, even when the latter have no asthenopic troubles, for they owe their origin to the nature of the myopia. Myopes learn to converge to the distance of their far point, without exerting the accommodation ”

“ Owing to the difficulty of reconciling these facts on the basis of the earlier theories, there is now a growing disposition to attribute myopia to hereditary tendencies;6 but no satisfactory evidence on this point has been brought forward, and the fact that primitive peoples who have always had good eyesight become myopic just as quickly as any others when subjected to the conditions of civilized life, like the Indian pupils at Carlisle,7 seems to be conclusive evidence against it. ”

“ If you could see my records, and count the number of cases where blindness is given as the result of straining nearsighted eyes, you would realize with me that progressive myopia should be classed as one of the preventable eye diseases, and a vigorous campaign waged against the marriage of persons so affected. Nearsighted people should be especially careful to avoid eyestrain, and should not work by artificial light. ”

“ Likewise the correction of myopia, by increasing the far point, may diminish the amount of convergence necessary for near vision. [Pg 131]
Prisms for constant use are often prescribed, so placed as to help the weak muscles and counteract the strong. For instance, in esophoria we find the prism which, base in, will produce orthophoria for distance and prescribe a quarter of it, base in, before each eye. ”

“ The highest degrees of eccentric fixation occur in the high degrees of myopia, and in these cases, since the sight is best at the near-point, the patient is benefited by practicing seeing worse at this point. ”

“ The imagination cure is the quickest and most satisfactory cure of myopia. Use two Snellen test cards, one held at one foot or nearer, or at a distance where you can see it best; the other placed at five feet or further. Look at the first letter of one of the lines of the near card and with the eyes closed remember it for half a minute or longer. ”

“ That the human eye resents glasses is a fact which no one would attempt to deny. Every oculist knows that patients have to "get used" to them, and that sometimes they never succeed in doing so. Patients with high degrees of myopia and hypermetropia have great difficulty in accustoming themselves to the full correction, and often are never able to do so. ”

“ All persons, without exception, who can see or read diamond type at the near-point, no matter how great their myopia may be, or how much the interior of the eye may be diseased, become able, as a rule, to see black with their eyes closed and covered more readily than patients with hypermetropia or astigmatism ”

“ The young eye, for example, is too flat (hypermetropic) —made to focus only on objects at a distance. Close application to print, or even to weaving mats or folding bits of paper accurately, causes an overstrain on the eye, which not only results in the chronic condition known as myopia,—short-sightedness,—so common to school children, but which acts unfavorably on the constitution and on the whole development of the child. ”

“ The eye with simple myopia is not credited with this capacity, because an increase in the convexity of the lens, which is supposed to be all that is accomplished by accommodative effort, would only increase the difficulty, and this, it is believed, can be overcome, in part, by alterations in the curvature of the lens. ”

“ When nearsightedness is discovered early, and glasses are given that make distant vision normal, and all needless near work forbidden, the myopia may be held in check, and any considerable increase prevented. Teachers are usually the first to notice such defects, but many parents do nothing when their attention is called to the matter. But happily these conditions are improving, and the school nurse and school clinic, and all the clinics maintained by public and private charities, are accomplishing wonderful results. ”

“ There are other injuries resulting from the reading habit in young children which concern the eyes directly. So much has been said and written lately about the increase of myopia and other defects of the eye among school children, that I shall merely refer to this subject here. Upon entering school, children are practically free from these defects. ”

“ In view of the prevailing theories about the relation of heredity to myopia, this picture is particularly interesting. A decline in visual acuity at the distance, however, is no more a peculiarity of civilization than is a similar decline at the near-point. ”

“ Long-sight or Hyperopia, and Short-sight or Myopia.—The eye is not in all cases perfectly formed. For example, persons may from birth have the cornea too prominent or too flat, or the lens may be too thick or too thin. In either of these conditions sight will be more or less defective from the first, and the defect will not tend to disappear as life advances. The most common imperfection, however, is in the shape of the globe ”

“ 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. ”