CHAPTER XIII ABNORMAL TENSION OF THE EYEBALL (Part 1)

CHAPTER XIII ABNORMAL TENSION OF THE EYEBALL Although the tension of the eye varies within rather wide limits we need to be able to recognize the condition when it is either above or below normal, for both an increase and a decrease are patho- logical symptoms. The simplest and most useful method of test- ing the tension is to have the patient look down, to place the tips of the two forefingers on the upper lid near the margin of the orbit, and to press with them alternately upon the eyeball, just as we examine a swelling for fluctuation. The sense of touch has to be educated by testing the tension of many normal eyes in this manner, and the physician soon learns to detect any marked variations, al- though slight ones may evade him because he can have no absolute standard as a basis for comparison. We should compare the ten- sion of the two eyes in every case, and we press more firmly than usual when the lid is cedematous, as the cedema imparts a cushiony feeling of softness to the finger. Following the suggestion of Bowman we designate normal tension as Tn, a questionable rise as + ?, a slight but distinct rise as + 1, a considerable increase as + 2, and stony hardness as + 38. Decreased tension is designated in like manner as —1, —2, and —38. According to Schioetz the tension varies normally between sixteen and twenty-seven millimeters of mercury, and can be measured more accurately by the tonometer devised by him, or perhaps still better by the modification proposed by Gradle. This instrument does not supplant, but it supplements the use of the fingers, as its systematic employment enables us to judge somewhat concerning the state of affairs within the eye, es- pecially when the tension is increased. Its measurements are not absolutely accurate, so it should be applied three times in each ex- amination and the readings averaged. After the eye has been anesthetized with a two per cent. solution of holocaine the patient is placed on his back, his head bent rather backward so that his eyes are directed upward, he is told to look straight up, the lids are 279 280 ' _-DIAGNOSIS FROM OCULAR SYMPTOMS separated with care to make no pressure on the eyeball, the instru- ment is placed on the cornea, and the number of millimeters of mer- cury necessary to indent it is read on the scale. Weights have to be used in addition if the tension is plus, and then the tension is deter- mined in millimeters of mercury by reference to a chart. GLAUCOMA Of all the diseases of the eye glaucoma probably is the one most often mistaken for some other, more curable condition, and such an error is almost invariably attended by disastrous consequences. Many years of experience have shown ‘that when this disease has once become firmly established we may delay its course and enable its victims to retain some sight for a good while, as long as they live in many cases, for the majority of the patients are elderly, but that it continues to progress either slowly or rapidly in spite of all that we can do. An early diagnosis is extremely important because a cure can be effected only when treatment is instituted during an early stage, and yet the fact that it is made so seldom, especially by those who see comparatively few cases of the disease, is not a matter of surprise when we consider the wide variations in the subjective and objective symptoms which are presented in its different forms, and the resemblance these symptoms bear to those produced by other conditions of the eye, as well as occasionally to those which are char- acteristic of certain general diseases. The symptoms common to all forms of glaucoma are a loss of sight, which may be rapid or very slow, an increase of tension that ranges from the upper limit of normal to stony hardness of the eyeball, an excavation of the papilla that is diagnostic when fully developed, and a contraction of the field of vision which begins and is most pronounced on the nasal side. The combination of any two of these symptoms may suffice for the diagnosis, but the symptom which is the most characteristic at all stages and in all forms of the disease is an increase of tension. Even when the increase is not apparent to the palpating fingers, it may be demonstrated to be present, at least at intervals, by systematically repeated examina- tions with the tonometer. The tension should be tested with the fingers as a routine part of the examination of every eye, and when this is supplemented by a test of the vision, a perimetric examina- tion of the field, and an ophthalmoscopic examination of the in- ABNORMAL TENSION OF THE EYEBALL 281 terior of the eye, there is little danger that a case will escape our observation. A glaucomatous excavation begins sharply at the edge of the papilla, which sometimes is surrounded by a yellowish gray ring, the so-called halo, and we must be careful not to mistake this for a part of the papilla itself. In most cases we can make out a line of separation between the papilla and the halo because the two differ slightly in color, and sometimes the line is very clear because of the presence of a scleral ring. The vessels hook over the margin of the papilla and do not seem to be continuous with those that lie in the floor of the excavation. As long as the excavation is shallow the color of the papilla may be good, but as it becomes deeper the color changes to bluish or gray, and when it is very deep dots that mark the apertures of the lamina cribrosa may be seen in the floor. The retinal veins are broad and tortuous, the arteries are apt to be engorged and to pulsate at first, but later they become small. These are the essential points that mark an excavation of the papilla to be glaucomatous, but the different forms of excavation that are met with and their differentiation will be given in the study of the fundus. : Glaucoma is secondary when it occurs as a complication of some other lesion of the eye, and is unilateral in most cases. Hemorrhagic glaucoma may be considered a variety of the secondary. Primary glaucoma comes on without known cause as acute inflammatory, chronic inflammatory, simple, and infantile, the symptoms of which differ so widely that at first we are apt to find it hard to believe them varieties of the same disease, but all terminate in absolute glaucoma, and are very closely related. Prodromal Symptoms of Glaucoma It is unfortunately the fact that while the premonitory or pro- dromal symptoms which usually precede an attack of acute glau- coma may attract the attention of the patient sufficiently to cause him to consult a physician, they are often considered by him to be of no importance, and consequently the disease is neglected at the very time it is most susceptible to treatment. When an elderly patient suffers from facial neuralgia or headache, especially if it is associated with loss of sleep and of appetite, it is worth while to examine the eyes. The neuralgia usually affects the first or oph- 282 DIAGNOSIS FROM OCULAR SYMPTOMS thalmic branch of the fifth nerve, but the second branch also may be affected and the trouble may seem to be situated in the teeth. The toothache has been so marked in some cases that healthy teeth have been drawn in the hope of obtaining relief when the trouble really was in the eye. In other cases this pain is not severe and an ob- servant patient may have noticed that objects have seemed misty at times, or that rainbow colored rings have appeared about lights, but such information is not volunteered very often, and we must avoid direct or leading questions in regard to such visual symptoms because many patients are led to believe that they have had them after they have been suggested. These prodromal symptoms are apt to make their first appearance during a period of mental stress or of bodily fatigue, and to pass away in a few hours, which is one of the reasons why little attention is likely to be paid to them. In still other cases the only premonitory symptom of the onset of glaucoma seems to be an unusually frequent change of presbyopic glasses. None of these symptoms are necessarily indicative of a threatened attack of glaucoma, but when they happen to be, and we examine the eye while they are present, we find the tension increased, usually about + 1, and can see by oblique illumination a slight ciliary in- jection, a slight diffuse cloudiness of the cornea, a rather shallow anterior chamber, and a dilated pupil which does not react well to light. With the ophthalmoscope we may see a venous engorgement and an arterial pulsation of the retinal vessels, but no typical ex- cavation of the papilla. If the attack happens to be the first we are not likely to be able to find anything abnormal in the eye after the symptoms have passed off, but, if we can find no evident cause for the symptoms elsewhere, our suspicions should be aroused, and the patient should be urged to have an immediate examination in case he ever has a second attack. We cannot tell at this time whether the disease will assume the acute, or the chronic inflamma- tory type, but an iridectomy probably will effect a permanent cure. Acute Inflammatory Glaucoma Should the disease assume the acute form the patient will be seized at some subsequent date with intense pain radiating through one side of the head, nausea, vomiting, and prostration, usually dur- ing a period of weakness following unusual fatigue, great mental ABNORMAL TENSION OF THE EYEBALL 283 anxiety or shock, or some other debilitating influence, like hemor- rhage. ‘These symptoms are apt to be so pronounced as to suggest trigeminal neuralgia, migraine, meningitis, gastric trouble, influenza, or some other disease. The patient may or may not notice that the pain starts from the eye, and if he does not this organ is quite likely to escape attention unless we examine it habitually in such cases. If we find the upper lid oedematous, the eyeball reddened, the con- junctiva perhaps chemotic, and sometimes with a little discharge, we know that the eye is either the seat of the trouble, or is suffering from an intercurrent affection. The only ocular conditions that can give rise to such grave general symptoms are a violent orbital cellu- litis, a severe iridocyclitis, and acute inflammatory glaucoma. If there is exophthalmos we look for other symptoms of the first, if there is not, a cellulitis is excluded. If the tension of the eye is about normal, the pupil small and irregular, the iris muddy with many posterior synechie, and little deposits can be seen on the lower part of Descemet’s membrane, the disease is iridocyclitis, but if the tension is + 2 or + 8, the pupil dilated. and oval, the cornea anesthetic and hazy, and the anterior chamber shallow, we have to deal with an acute inflammatory glaucoma. If there is no exophthalmos, the tension is normal, and the symptoms of an iridocyclitis are absent, the affection of the eye is intercurrent, and is not the cause of the general symptoms. When the tension is + 8 we cannot dent the eyeball with the finger, the cornea is anesthetic and very cloudy, the anterior cham- ber is almost obliterated, the oval pupil is dilated extremely, the pain is atrocious, the vision is very poor and in imminent danger of being lost. In the rare cases of fulminating glaucoma the vision may be destroyed within a few hours, the attack may not have been preceded by any premonitory symptoms, the pain is excruciating, and the violence of all of the acute inflammatory symptoms is ex- treme. The symptoms abate after a while in the majority of cases of acute inflammatory glaucoma, and the vision improves, but it never again becomes as good as it was before the attack. Certain signs are left behind from which we can infer what has taken place and recognize the predisposition of the eye to further attacks. The anterior ciliary veins remain distended, the anterior chamber remains shallower than it should be, while the pupil has at least a tendency to dilate, and reacts more slowly to light than is usual in persons of the same age. The papilla is apt to appear much reddened after 284 DIAGNOSIS FROM OCULAR SYMPTOMS the first acute attack has passed off, but not to present a typical excavation, and an operation at this time is likely to be permanently successful. Unless interrupted by operation the course of an acute inflamma- tory glaucoma is that the symptoms may or may not pass away completely. In the first case recurrent attacks, which, as a rule, are not as severe as the first one, take place at intervals, but the vision is left worse after each, a glaucomatous excavation forms in the papilla, and finally the eye is rendered totally blind. In other cases the first attack cannot be said to pass off entirely; the symp- toms are ameliorated, but persist, the tension remains above normal, and chronic inflammatory glaucoma supervenes. Chronic Inflammatory Glaucoma Although this form may set in with an acute attack, as has just been stated, it cannot be said to do so as a rule. Many aged pa- tients are not aware that they have any disease of the eyes, although they have had recurrent attacks of supraorbital or facial neuralgia, and have noticed at times that they could not see well. They have ascribed these symptoms to various causes, frequently to the fact that they were growing old, which also sufficed to explain to them why they have had to change their reading glasses so often. Yet these are the ordinary subjective symptoms of chronic inflammatory glaucoma. This form of the disease begins like the prodromal stage of the acute with an attack of supraorbital or facial neuralgia, and a cloudi- ness of the cornea which causes hazy vision and colored rings about lights to be noticed by observant patients. This passes away in a few hours, and another attack ensues some weeks or months later, which likewise proves transient and generally leaves the eye in good condition. This is succeeded by others, with the intervals between them growing shorter constantly, and after a few have occurred permanent abnormal changes will be found to have taken place in the eye. Between the attacks we find the vision more or less im- paired, the tension above normal, dilated, tortuous veins at the insertions of the muscles into the sclera, a shallow anterior chamber, a dilated pupil which does not react well to light, a contraction of the nasal portion of thé field, and a glaucomatous excavation of the papilla, and we find all of these symptoms to be intensified after ABNORMAL TENSION OF THE EYEBALL 285 each successive attack. It frequently happens that as long as only one eye is affected the patient does not realize that there is anything the matter with his eyes, and it is only after the second has been attacked and its vision fails that he seeks our aid in his search for a pair of glasses to enable him to read with comfort. Often much valuable time is lost through visits to opticians and optometrists, who are extremely unlikely to be able to recognize the presence of the disease, for if such cases can be operated on early enough a cure may be effected, or the progress of the disease delayed sufficiently to give the patient vision for the rest of his life, while if too great an advance has been made the best we can do is to delay its progress as long as possible. When the disease is far advanced the vision is very poor, the eye has a peculiar dead appearance, broad, dark vessels ramify over the sclera and form a plexus about the cornea, the cornea is somewhat anesthetic and not perfectly clear, the anterior chamber is very shallow, the pupil is widely dilated, oval vertically, and reacts to light slowly, or not at all, the iris is atrophic, and we get a greenish reflex from the lens. This greenish reflex is not a sign of cataract, as it has often been taken to be, but is to be obtained from all clear senile lenses when the pupils are dilated. ‘The tension is distinctly elevated, the field is contracted, particularly on the nasal side, the papilla is surrounded by a halo, is bluish or gray and deeply ex- cavated, the vessels hook over its margin, and their entrance into the nerve may be seen to be pressed over to the nasal side. The prog- nosis in this stage is bad. An eye which is suffering from chronic inflammatory glaucoma is liable to an acute attack, and as acute glaucoma sometimes passes over into the chronic form it is evident that these two diseases are closely related, and differ in the intensity of their symptoms, rather than in their nature. The essential features in both, from first to last, are an abnormally high tension, progressive loss of vision, con- traction of the nasal field, distention of the ciliary veins, abnormal shallowness of the anterior chamber, dilatation of the pupil, and excavation of the papilla. Simple Glaucoma While the inflammatory varieties of glaucoma can be recognized with comparative ease, if we always investigate the condition of the eye in every case of mild or severe trigeminal neuralgia with which 286 DIAGNOSIS FROM OCULAR SYMPTOMS we meet in elderly patients, our attention