REFRACTION. * TAKING A COURSE IN REFRACTION. WE large field of usefulness and profit which is open to the general practitioner who will fit himself for, and will undertake. the work of eye refraction. There is no class of medical work which, for so moderate an amount of intelligence and care, yields such uniformly satisfactory and gratifying results to both physician. and patient. Unlike every other department of medical practice, it is an exact science, and the precision of its results. serves to establish in the patient's mind a feeling of confidence in the physician such as none of the less certain branches of practice can create. Nor is there any class of cases, occurring in the ordinary routine of practice, for which, for the same outlay of time and skill, as large a fee may be legitimately charged and will be as cheerfully paid. It is a great pity that the general practitioner has neglected and ignored this work, leaving it to the eye specialist, who of course cannot meet the demands of the public-for the need of glasses is more widespread than any other physiological need-and hence it has passed largely into the hands of the opticians, who have in several States secured legislative recognition and license to perform refraction. Such a situation is entirely unnecessary and uncalled for. There is no good reason, except that of an inexcusable "rut," why the general practitioner of medicine should not be doing this work. Everything else being equal, he is the proper and logical person to do it. He is entitled to it by every consideration of right and ethics, and ought to be so by virtue of his qualifications. Ay, there's the rub. For so many years the work of refraction has been regarded as foreign to the general practitioner's sphere that the medical schools have paid but scant attention to the subject, leaving it almost wholly to the postgraduate colleges, to which a man is supposed to go who proposes to adopt the specialty of the eye; and the medical student himself, accepting the general view of the matter, has been content to let the subject slide, and the result has been that medical graduates have been turned out with practically no working knowledge of refraction at all. So the breach between them and this class of work has widened, until they feel themselves utterly unqualified for it even though they might have an inclination to undertake it. It appears that the pity of the situation has at last begun to dawn upon organized medicine-due, largely, to the inroads being made by the optometrists in the various States-and a movement is now on foot by a committee of the American Medical Association to promote the practice of refraction by the family physician, and to brace up the teaching of the subject in medical colleges, so that future generations of medical practitioners may be expected to understand and to perform the work. But, in the meantime, what of those men who are already in practice, who realize the advantage a working knowledge of the subject would be to them, who would gladly undertake the work, but who caunot return to school, and can hardly afford the time and money to attend a postgraduate college? And even for those who could and would attend such a postgraduate school, the ordinary eye, ear, nose and throat colleges do not afford the opportunity desired. The practitioner does not want to make himself a specialist in eye, ear, nose and throat work-nor even in eye work. He wishes to spend neither the time nor the money in these specialties. He wants only to learn refraction. But the post-graduate schools offer him the whole thing or nothing. Happily there are, scattered throughout the country, a few good schools of refraction, where the subject is taught thoroughly and efficiently, in the shortest possible time consistent with these two qualities, and at a moderate expense. Some of these will be found in our own advertising pages. The fact that they are outside the jurisdiction of organized medicine detracts nothing of their efficiency, or of their value to the doctor who wishes to equip himself for this kind of work. For those physicians who do not feel that they can leave their practices even for a short time, there are adequate courses in refraction by correspondence, by which any intelligent medical man, with his previous scientific training, can, with a little application, acquire a proficient working knowledge of the subject, to which his personal experience will add all that is. necessary. We earnestly urge our readers to take this matter up, and get out of it, for themselves and their clients, all there is in it. It will pay the average physician more, and give him a wider range of usefulness, than a similar course in, let us say, major surgery. For the general practitioner has, in these modern days, but little opportunity to perform major surgery; cases of that kind are, in any event, few and far between; and in order to undertake them at all, the physician must have arduous and expensive training. But cases of eye refraction are more numerous, as we have said, than any other kind; they can always, with patience and care, be worked out to a satisfactory conclusion; and they will always command a fee equal to the obstetric fee of the locality. in which the physician practices. It is because of our conviction on this matter that we conduct from month to month this department of Refraction, by which we hope to promote the practice among our readers and to assist them in their work. It is, however, impossible for us to give, in this limited department, a complete or thorough course of instruction in refraction. We therefore recommend our readers to take a systematic course, wherever and whatever method their judgment directs them. We believe it will be an excellent investment from every point of view. And we stand ready, of course, to render whatever counsel and assistance may be in our power to those who desire to carry out such a course. CATECHISM OF REFRACTION. (Continued from page 32 in January Issue.) Correction of Astigmatism. Q. What are the chief meridians in astigmatism? A. As the cornea is a sphere, naturally if one of its meridians be unduly flattened or convex, the meridian at right angles to it will be correspondingly affected in the opposite way. These are called the chief meridians and are always at right angles to each other. Q. What is the prismatic lens test in astigmatism? A. Of the rays which pass through the most convex meridian of the eye, the blue rays come to a focus first, while of those which pass through the least convex meridian, the red focus first; and as these two meridians are at right angles to each other, the candle flame, seen through the chromatic lens, appears as two bars of blue and red light drawn out at right angles to each other. This test applies only to high degrees of astigmatism. Q. What is the significance of the test type in astigmatism? A. It is certain that rays of light from the distanct type cannot focus upon the retina in both meridians at once, hence the distant type cannot be clearly read by the astigmatic eye. Q. Describe the wheel test? A. The astigmatic wheel or fan is a series of black lines drawn to correspond with the meridians of the eye. It is evident that the line which corresponds to the defective meridian of the eye will be seen, not as a clear black, but as a faint gray or brown. And it is further evident that that spherical lens which will render this faint line clear and black is the measure of the character and degree of the defect in that meridian. We therefore ask the patient to pick out the line in the wheel which looks faintest, and try successively convex and concave spherical lenses until we find the one which renders this line distinct and black. This lens, when found, is the measure of the cylinder which, with its axis at right angles to the faint meridian, will correct the astigmatism. This applies only to simple astigmatism. Q. What is the stenopaic slit, and how used? A. It is an opaque disc with a narrow slit in it, the effect of which, when mounted before the eye, is to cut out the rays of light from all meridians of the eye except that which corresponds to the slit. By turning the disc around the slit may be made to coincide successively with all the ocular meridians. Now, if the eye be normal, vision of the distant type will be equally good no matter in what meridian the slit lies. But if one of the meridians of the eye be defective in refraction, then, when the slit is turned to coincide with that meridian distant vision will be poor. It will, in fact, be worst when turned to that meridian. and best when turned at right angles to that meridian. If, now, a spherical lens be found which will render vision through the slit, when turned to its worst meridian, normal, then that lens is the measure of the cylinder which, when placed with its axis at right angles to the defective meridian, will correct the astigmatism. Q. What is compound astigmatism, and how corrected? 2. Compound astigmatism is that form of astigmatism in which the two chief meridians of the eye are both defective in the same way, i. e. both myopic or both hyperopic, so that a lens of the same character, but of different strength, is necessary to correct vision when the slit is at its worst and at its best angle. Now it is plain that if the worst meridian be corrected to the extent of the difference between it and the best meridian, i. e. if it be brought up to the same degree of defect as the best meridian, then the defect in the two meridians being the same, the error is no longer one of astigmia, but of ordinary spherical refraction. The rule, therefore, in compound astigmatism, is to correct the difference between the two meridians with a cylinder, at right angles to the worst meridian, and the remainder of the error with a sphere of the appropriate curvature and strength. Q. What is mixed astigmatism? A. Mixed astigmatism is that form in which both meridians are defective, but in different curvatures, i. e. one myopic and the other hyperopic, so that with the slit at its worst angle a spherical lens of one curvature is required to make vision normal, and at the best angle a spherical lens of the other curvature. Now it is clear that if the one of the meridians be over-corrected so as to make it of the same curvature and degree as the other, then the remaining error is a spherical one, and can be corrected with a spherical lens of proper curvature and strength. It is customary to over-correct the meridian of least convexity, i. e. the one requiring the plus lens. Q. What is the retinoscopic finding in astigmatism? A. Usually the edge of the shadow is oblique in astigmatism. This, however, is not always the case, especially in vertical astigmatism. The only safe method to follow in detecting and measuring astigmatism with the mirror is to test both meridians, rotating the mirror successively at right angles to each chief meridian. Each meridian must then be corrected separately with its appropriate spherical lens, and the proper cylindrical or combined correction estimated in the same way as described in connection with the stenopaic slit. In compound or vived astigmatism, when one of the eridians has received its spherical correction, the reflection of the retinoscope is usually seen as a band of light lying across the pupil, with its axis subtending the uncorrected meridian. In slight cases this band does not appear, hence it must not be regarded as a sine qua non. AFTERMATH OF EYE-STRAIN. Sydney Stephenson, in The Lancet, sets forth the following general considerations of eye-strain and the data upon which our knowledge of it is based: How to Recognize Eye-Strain. Whenever a headache, migraine, vertigo, or "tic" is induced or made worse by use of the eyes and relieved by rest we may safely assume it is due to eyestrain. That supposition is strengthened (paradoxical though it may seem) if the patient possesses sight which when estimated by the test-types is found to be normal or super-normal. It is a suspicious circumstance if headache is complained of after a visit to a theatre or a picture gallery, or a journey by train, tram, or car. There is more than the proverbial grain of truth in the epigram of an American physician who remarked. that there was nothing particularly characteristic about the headache of eyestrain, except that the subject rarely suspected that his eyes were at fault. This point has been emphasized anew by Dr. James Hinshelwood, of Glasgow.2 Then there is the fact that an ocular reflex can often be inhibited for the time being by putting a drop of atropine (or other cycloplegic) into the patient's eyes. Lastly, it can scarcely be repeated too often that no eye can be pronounced to be normal unless its refraction has been estimated by a competent surgeon under the influence of a cycloplegic. The Kind of Patient. Slight errors of refraction are most likely to cause distress in persons who have inherited or acquired an unstable nervous system, the "neuropathic" disposition, as Dr. George T. Stevens called it. In my opinion, this factor dominates the entire question of eye-strain, especially in its severer manifestations. Women and children suffer more readily than men, among whom the highly strung are the more liable. The higher classes are more prone than the lower; the cultured than the uncultured. Clerks, teachers, stenographers, dressmakers, typewriters, students, and others compelled by occupation to use the eyes for hours at a time are particularly subject to the symptoms of eyestrain. The general health of the patient is by no means devoid of influence. It is clear that an error of refraction or of muscular balance is more likely to cause distress if the patient is in poor health, as from influenza, or debilitated, as from lactation or recent confinement. It is not uncommon for the trouble to disclose itself for the first time under such circumstances, even although the underlying ocular defect may have existed from childhood or even have been congenital. How Eye-Strain Shows Itself. By common consent, headache is the commonest reflex manifestation of eyestrain. It has been variously estimated that headaches of ocular origin form from 60 per cent to 90 per cent of all cases of headache. In an analysis of 106 instances of reflex neuroses probably due to the eyes, Dr. H. B. Ellis found that headache was present in 87.7 per cent, digestive and assimilative disorders in 5.7 per cent, blind spells in 3.8 per cent, mental symptoms, loss of memory, &c., in 1.9 per cent, and insomnia in 0.9 per cent. The late Mr. Simeon Snell5 found that of 800 consecutive refraction cases that came under his notice 162—that is, about 1 in every 5-sought advice in consequence of headache. The Kind and Magnitude of the Error. Of all errors of refraction slight grades of hyperopia, and particularly of hyperopic astigmatism, are those most likely to cause distress. The tendency is greatly increased if the error be asymmetrical as regards the axis of the cylinder or be unequal in the two eyes. On the other hand, myopic defects usually produce poor sight rather than the common reflex manifestations of eye-strain, such as aching eyes or head. The results of strain are more likely to occur when the underlying error of refraction is so small that it can be mastered for the time being by action of the ciliary muscle. To put the matter in another way, a large error of refraction, which cannot be overcome by those means, leads, as a rule, to defective sight and not to eye-strain. "The smaller the error," it has been aptly said, “the more likely is eye-strain to be present, and also, unfortunately for the patient, the more likely it is to be overlooked." Patients with eye-strain, then, seldom show any serious departure from normal when their relative visual acuity is estimated at Snellen's test-types, an important point for the physician to bear in mind. Method of Estimating the Error. The days are fairly outlived when it was seriously taught that an astigmatism of less than 1.00 D., provided it caused no interference with sight, might be safely disregarded. It is now recognized that under some conditions an amount of astigmatism of no more than 0.25 D. or even 0.12 D. may cause intense discomfort. For the detection of such small errors our means of examination can scarcely be too accurate. It goes without saying that the surgeon himself must be well versed in refractions. He must be equipped with suitable lenses, correctly designed trial-frames, and properly illuminated and drawn test-types, and he should be expert in the use of the retinoscope and of other instruments of precision, such as the keratometer. Everything hinges upon exactitude. "It is the little, the inconsiderable thing, in refraction work upon which the relief of the reflexes depends" (George M. Gould). Now the precise determination of ametropia, especially the low degrees of ametropia, is not possible, I believe, unless the eyes be under the influence of some agent, as homatropine, hyoscin, or atropine, which is capable of paralysing the ciliary muscle, a cycloplegic in fact. In no other way, to my thinking, can the full measure of the defect be disclosed. In young persons, indeed, the accommodation is so active that it may conceal a hyperopia of several diopters, to say nothing of a considerable degree of astigmia. To a certain extent the remark is true of older patients also. Not only must the cycloplegic be of the right kind, but it must be applied until accommodation is placed wholly in abeyance, a point that should always be ascertained by means of a suitable test. Speaking generally, the most trustworthy results are obtained when the selected drug is applied to the eyes by the surgeon himself. A HELP TO EYESIGHT. Most people begin to notice failing eyesight at the age of fifty or a little. sooner. Many people find their eyes "stuck up" in the morning and it is some time before they can see clearly. Something can be done every day to benefit the eyes without taking up too much time, or interfering with other duties. Take a few drops of sweet oil, or any simple emollient, on the hands, and thoroughly massage the entire face, giving special attention to the region. about the eyes. Do not rub the eyeballs, but carefully rub the tissues above and below the eyes with the end of the fingers, drawing the fingers away from the nose outward. Continue this some minutes, then exercise the muscles that |