CHAPTER X Tue Iris (Part 2)

are bound together by a total posterior synechia. When the pupil is filled by an exudate lying on the an- terior capsule it is said to be occluded. When any such conditions as these are present at birth they are to be ascribed to an intrauterine inflammation, not to a developmental fault. Oval Pupil When a pupil is central, but oval in form we notice its size and the depth of the anterior chamber. [If it is large and the anterior chamber is evenly shallow we look for other signs of glaucoma; if it is large and the anterior chamber is unevenly deep, we have good reason to suspect a dislocation of the lens; if it is large and the anterior chamber is normal, the condition may possibly be congenital. If it is small we instill a mydriatic to ascertain whether it is held in this shape by posterior synechie, if these are absent we look for evidences of disease in the central nervous system, of which an oval or rather irregular pupil sometimes is symptomatic, and if no indi- cations of inflammation or disease, either past or present, can be found we may conclude it to be congenital. Corectopia In rare cases we may see in both eyes an oval or irregular pupil at some distance from the center of the iris, and be told that the malformation has been present since infancy; this is congenital corec- 210 DIAGNOSIS FROM OCULAR SYMPTOMS topia. Other members of the family are apt to have a like defect, as often it is hereditary. Frequently it is associated with a corre- sponding ectopia of the lens, or with some other abnormality of the eyes. To determine whether it was caused by a fault of develop- ment, or by an intrauterine inflammation, we test its reaction to light, for in the former case its reaction to light is likely to be per- fect, while in the latter the response is apt to be faulty because of adhesions, or of atrophy of the iris. As a rule, it is not difficult to differentiate congenital corectopia from a condition in which the pupil has been displaced from the center as the result of inflammatory adhesions of the iris to neigh- boring structures, such as may follow a wound, or the perforation of an ulcer of the cornea. In most of these cases the pupil is not only drawn to one side, but is much distorted, with a point extending toward the site of the lesion, where we are likely to find a prolapse of the iris, an anterior synechia, or an adherent leucoma. Some- times the pupil is drawn upward after a cataract extraction, and is not much distorted, while no such adhesion of the iris is visible. The history serves for differentiation. Polycoria A few cases of supernumerary pupils have been recorded, but there seems to have been in most of them a more or less regular central pupil with one or more dehiscences in the iris which were not provided with sphincters. The term has been applied erroneously to bridge coloboma, but we mean by polycoria the congenital pres- ence in the iris of two or more apertures which appear to be pupils. A somewhat similar condition can be caused by a gaping wound of the iris, by an iridodialysis, by an iridectomy that leaves the margin of the pupil intact, by the breaking down of a gumma, and by localized patches of atrophy, but the differentiation can be made easily, as a rule, from the history, and the presence of other signs of traumatism or disease. An interesting diagnostic point is that congenital polycoria is said not to interfere with vision, while arti- ficial apertures are apt to cause monocular diplopia. Iridodonesis By this term we mean that the iris can be seen to vibrate or tremble when the patient moves his eye. When this tremulousness THE IRIS 211 is well marked it is evident that the iris is not supported properly by the lens, which must be dislocated or absent, but if we look closely we can see a faint iridodonesis even in a normal eye when the pupil is much contracted. A well marked tremulousness of the iris can be present congenitally only in cases of ectopia or congenital aphakia; as a rule, it indicates that the lens is pathologically shrunken, dis- located, or has been removed. Iridodialysis When one side of the pupil forms a straight line we shall probably find a black segment at the corresponding part of the ciliary mar- gin of the iris, where the latter has been torn from its attachments so as to leave an aperture. This separation of the peripheral part of the iris is called an iridodialysis, and is the result of a traumatism, usually of a contusion. When it is small it may cause no trouble, but when it is large enough to act as a second pupil it is apt to cause monocular diplopia. In a very large iridodialysis the detached por- tion of the iris may be reversed so that we are able to see the black retinal layer; this is called anteversion of the iris. Inversion of the Iris In very rare cases after a contusion of the eye we may find that a portion of the iris has disappeared because it has been bent back- ward over the ciliary body. Should the entire iris be inverted in this manner the same appearance is produced as that presented in traumatic irideremia, and the differentiation cannot be made, as a rule, until after the recovery of the eye from the effects of the traumatism. In the majority of cases an inversion of the iris is associated with a dislocation of the lens, and it cannot take place unless the zonule has been ruptured. Irideremia A part, or the whole of the ordinarily visible portion of the iris may be absent either congenitally or as the result of traumatism. The differentiation is not very difficult. Total irideremia, in which no trace of the iris can be seen clini- cally, is very rare. The entire area covered by the clear cornea presents the solid black of the pupil, which gives a strange, ex- pressionless appearance to the face. With the ophthalmoscope we 212 DIAGNOSIS FROM OCULAR SYMPTOMS obtain the red reflex of the fundus throughout this area, and some- times we can see the ciliary processes. Most of these cases are con- genital, but the entire iris may be torn away as the result of a severe contusion of the eye, and either fall into the anterior chamber as a little, shrivelled, blackish or grayish mass, or be extruded from the eyeball through a laceration in the sclera, perhaps in company with the lens. Accidents have been known to occur in which the entire iris was torn away as the result of a violent movement on the- part of the patient, or of an unsteady hand on the part of the operator, when the iris had been seized for a proposed iridectomy, and left in the grip of the forceps outside of the eye. The same thing is done intentionally in the operation of iridenkleisis, which is rarely performed. The appearance after recovery in these cases is much the same as that of congenital irideremia, but the differentiation usually is easy, even when the history is unknown, for traumatic irideremia, or aniridia, nearly always is unilateral, while the con- genital variety is almost invariably bilateral. Out of 117 collated cases of the latter there were only two in which the defect was not total in both eyes, and only one patient had a complete iris. In addition to this, when an eye has suffered a traumatism sufficient to produce an avulsion of the iris scars can usually be found. Another point is that photophobia is very pronounced and annoying in trau- matic irideremia, if the eye otherwise is good, but seldom is present when the defect is congenital. Out of 164 cases of total and partial congenital irideremia photophobia was said to have been severe in only six, slight in twenty-nine, and quite a number of these patients had corneal troubles sufficient to account for the symptom. The absence of marked photophobia is particularly striking when the vision of the eye is good. Another guide is the position of the lens when it is displaced. A traumatic dislocation may be in any direc- tion, though it is not very apt to be upward, while in congenital irideremia it is common for the lens to become luxated upward gradually, inclining a little perhaps to one side or the other, to shrink, and to become cataractous. In partial irideremia a portion of the iris is wanting, while the rest is visible. Probably it is true that every case of congenital irideremia is partial histologically, as a rudimentary iris has been found in all of the very few cases that have been examined anatomi- cally. Pagenstecher, Lembeck, Debendetti, and Rindfleisch agree in describing this rudimentary iris as caught between two lamelle of THE IRIS 213 Descemet’s membrane, but for clinical purposes such an invisible rudiment might just as well be nonexistent. After two or three broad iridectomies have been performed beside one another in the same eye, the condition of the iris resembles that presented in many cases of congenital partial irideremia, yet it is not hard to distinguish these conditions. In most cases the history informs us aright, but the presence of a disease for which iridectomy is the correct treatment is not a safe guide, because glaucoma may occur in either total or partial irideremia. The presence of a cicatrix in the scleral margin is good presumptive evidence that an operation has been performed, but we can obtain positive proof from an ex- amination of the margins of the defect. If the design of the iris has been cut across and the sphincter is divided, we know that an iridectomy has been performed, for in a congenital defect the sphincter can be traced along its margin, growing narrower as it approaches the periphery, and the details are not interrupted sharply, although they are altered. The cause of congenital irideremia is unknown further than that it is apt to occur in families which have a hereditary predisposition to anomalies of the iris. In the majority of cases it is associated with developmental faults of other parts of the eye, or of other parts of the body. The ciliary processes, choroid, retina, and optic nerve frequently are defective or diseased, the cornea often is faulty and seems to be unusually prone to inflammation, and the lens is apt to become cataractous and to be gradually luxated upward, even when it appears to be normal at first. In a minority the irideremia seems to be the only defect, except that myopia is quite common, and good vision may be secured by correction of the refractive errors. Coloboma of the Iris A congenital cleft of the iris that resembles a Gothic arch with its apex downward, or downward and inward, is a congenital coloboma. When the apex is visible and the fissure evidently does not involve the whole width of the iris the coloboma is partial; when the apex is hidden behind the opaque margin of the cornea it is total. A partial coloboma may vary in size from a notch in the lower margin of the pupil to a cleft which extends nearly to the root of the iris. A coloboma commonly is supposed to be caused by a faulty closure of the fetal cleft, but the correctness of this theory has been 214 DIAGNOSIS FROM OCULAR SYMPTOMS questioned of late by some embryologists who maintain that the fetal iris has no cleft at any time during its development. If these in- vestigators are right we are just as much in the dark with regard to the origin of coloboma as to that of irideremia. Sometimes it is met with in several members of the same family, so there may be a certain amount of hereditary predisposition, but this is not as marked as it is in many other congenital defects. It is associated frequently with coloboma of the ciliary body and choroid, sometimes of the sheath of the optic nerve, and of the lens, but it is also met with alone. By itself it does not impair the vision or cause photophobia. A band of tissue passing across the defect from one side to the other converts it into a bridge coloboma. A strip of tissue with- out pigment running downward in the iris is called a false colo- boma. Beard gives the same name to a dark stripe caused by an ectropion of the uvea when this physiological lump of pigment causes the pupil to look as though it were elongated downward. A con- dition in which the stroma of the iris is absent so as to expose the retinal layer, causes a similar appearance. Ordinarily we speak of the defect produced in the iris by an iridectomy as an artificial coloboma; many writers call congenital deficiencies of varying size that extend in any direction from the pupil except downward, atypical colobomata; and great confusion exists in literature be- cause of the way in which this term is used. One writer limits the size of a coloboma to one-fourth of the iris and says that it must always extend downward; another says in his description of what he called a coloboma that the entire nasal third of the iris was want- ing and that the balance formed a crescent; a third calls a case in which the central, superficial layers of the iris were absent, so as to leave a bright ring of color about a dark membrane which contained a round pupil in its center, an incomplete coloboma.’ A better name for the last would seem to be either partial superficial irideremia, or congenital exfoliation of the iris. Whether a fissure of the iris that extends downward is due to a faulty closure of the fetal cleft or not, its frequent association with a similar cleft of the choroid and ciliary body marks it as different from like defects elsewhere in the iris, which seldom if ever have similar associations, and entitles it to a distinguishing name. The others can be included properly under the term partial irideremia, or partial aniridia. THE IRIS 215 IRITIS When a patient has acute pain which is worse at night, radiating over the brow and temple of one side of the head, extending back perhaps as far as the neck, the diagnosis of supraorbital neuralgia is too apt to be made without even looking at the eye, and to be thought sufficient, especially when it agrees with the patient’s own preconceived opinion. Yet just such a pain may be symptomatic of an ulcer in the cornea, an iritis, or a glaucoma, and eyes have been lost from each of these diseases because no attempt was made to ascertain whether the origin of the neuralgic pain was in the eye. In other cases the eyes were thought to be suffering from a slight intercurrent conjunctivitis of no importance, or to be reddened and lacrimating in sympathy with the affection of the trigeminal nerve. It does not seem safe to make any exception to the rule that in every case of severe supraorbital pain the eye should be examined thor- oughly enough to exclude any of these diseases. If the lid is swollen and the eyeball reddened at all, we may feel pretty confident of find- ing the trouble there. An ulcer of the cornea in such a case is plainly visible and can be overlooked only through carelessness or pure neglect. If the cornea, iris, pupil and tension appear to be normal, we must search carefully for a small foreign body as the possible cause, but in the great majority of cases we shall find either a small, irregular pupil, indicative of iritis, or a dilated pupil with increased intraocular tension, equally diagnostic of glaucoma. The differentia- tion of these two diseases will be given more at length under plastic iritis, and under glaucoma. When we see in the eye of a patient who complains of this neuralgic pain which is worse at night, a swollen upper lid, an extensive, dark episcleral injection, and a dis- colored, muddy looking iris with a small irregular pupil, the diag- nosis of an acute plastic iritis, the most common variety, is positive and easily made; but then our work has only just begun—we have to determine its etiology if possible. Less often we meet with the serous and purulent forms of iritis, and we need to be able to recog- nize all under different conditions, for any type may run an acute, a subacute, or a chronic course. An iritis that appears as a compli- cation of a severe inflammation of the conjunctiva, cornea, sclera, or of some other part of the uvea is called secondary, all other forms are primary. Occasionally the inflammation may be chronic from 216 DIAGNOSIS FROM OCULAR SYMPTOMS the start, as in some forms of tuberculous iritis, the quiet iritis some- times met with after operations for cataract or glaucoma, and in plastic iridochoroiditis. The subjective symptoms are pain, photo- phobia, lacrimation, and impairment of vision. The more acute the attack the more severe the pain, is a rule to which there are excep- tions. Photophobia and lacrimation often are not very severe, and in the early stage of a purely chronic iritis the only subjective symptom may be an impairment of vision. Hyperzemia of the Iris When we see an iris that is discolored, the hue darkened, or per-- haps with a reddish tone when the original color was dark, or green- ish when it was blue or gray, the pupil contracted or less responsive than normal to darkness or a mydriatic, but with no