CHAPTER IX Tue SCLERA AND THE ANTERIOR CHAMBER (Part 1)

CHAPTER IX Tue SCLERA AND THE ANTERIOR CHAMBER THE SCLERA It is not common to find anything of pathological interest on the sclera, aside from the injection of the minute episcleral vessels about the cornea in inflammations of that tissue, or of the iris and ciliary body, and the engorgement of the anterior ciliary veins when the eye is suffering from glaucoma, but occasionally we see scleral conditions that are of more or less importance. ‘These in- clude spots, protrusions, and inflammations. PIGMENTATIONS OF THE SCLERA A congenital, irregular, brown patch is to be seen on the sclera, quite frequently in negroes, much less often in brunette whites, which is of no pathological signification. Rare cases of pigmenta- tion in Addison’s disease have been reported, and these sometimes are situated symmetrically in both eyes near the cornea. Little- black or brownish stains may indicate where grains of powder have been driven into the tissue through the conjunctiva, and silver has been held responsible for a bluish stain in a few cases. Of much greater importance is a roundish, slate-gray, or blackish spot, which is accompanied by a history of a past inflammation of the eye that resisted treatment for a considerable time; such a spot may be single, or a number of them may form an arc or a circle about the cornea, when we know that the eye has suffered from recurrent attacks of scleritis, each of which has left a cicatrix. STAPHYLOMA OF THE SCLERA A protrusion outward of some portion of the sclera, with few or no signs of inflammation of the eye, is a staphyloma. The only ones that are visible externally are those situated in front of the 194 THE SCLERA 195 equator of the eye, which are called anterior, and those about the equator itself, which are known as equatorial. When a portion of the back part of the sclera bulges outward to form a posterior staphyloma, we can sometimes make out a localized concavity. in the fundus with the ophthalmoscope; this will be discussed under the lesions of the fundus. An anterior or equatorial staphyloma is dark because the sclera at this point has been so thinned as to allow the color of the subjacent uvea to become visible. An anterior staphyloma over the ciliary body is known as ciliary, one between this place and the cornea as intercalary. Sometimes an intercalary staphyloma involves both the sclera and the cornea. A staphyloma is caused by a local weakness of the sclera that renders it unable to withstand the intraocular pressure. When the latter is above normal in a young child the entire sclera is apt to stretch, but in older persons it is more likely to give way in places. The cause of the weakness in the posterior segment that gives rise to a posterior staphyloma is unknown, and that which operates in the anterior segment cannot always be determined positively, but in the great majority of cases it is the thinning of the tissue pro- duced by disease or traumatism. Occasionally we see one or more anterior or equatorial staphylomata in old cases of absolute glau- coma, or one caused either by the imperfect cicatrization of a wound, or by the erosion produced by a tumor, but usually an anterior staphyloma bears witness to a past scleritis. This is par- ticularly true when several have been formed about the cornea, or when the latter has been projected forward by the yielding of a dark band which surrounds it in the sclera. <A ciliary, or an inter- calary staphyloma is a serious menace to the eye, as it is very apt to induce secondary glaucoma. SCLERITIS When we see a dark red, or bluish-red protrusion of the sclera, with a rather indistinct margin, associated with a violent irido- | cyclitis and its usual subjective symptoms, we have to deal with a deep scleritis. Both eyes are apt to be affected, and we may be able to see opacities in the vitreous, or masses of pigment in the fundus that attest the presence of a choroiditis. Sometimes a sclerosing keratitis is present, or several dark spots may be visible about the cornea, which show where one scleritic node has succeeded 196 DIAGNOSIS FROM OCULAR SYMPTOMS another. Occasionally there is a uniform swelling about the cornea instead of isolated prominences. The combination of iridocyclitis with an angry swelling over the site of the ciliary body, to which the conjunctiva is not adherent, makes the diagnosis of this rare disease fairly easy. Whether it appears primarily in the sclera and spreads to the uvea, or starts in the ciliary body and involves the sclera secondarily, is still an open question. The result is apt to be destruction of the eye, whether the tissue of the sclera is thinned so as to give rise to the dark cicatrices or staphylomata already described, or the sclera is enormously thickened, as in the variety known as brawny scleritis. Brawny, annular, or gelatinous scleritis appears typically as a gelatinous, brownish red infiltration of the conjunctival, episcleral, and scleral tissues, most marked close to the limbus. The succulent swelling often overhangs the cornea, and extends back a variable distance, to the equator or farther. The blood vessels and lymphatics are dilated enormously. Pain is distressing and tenderness is acute. A sclerosing keratitis, accompanied by both deep and superficial blood vessels, advances until it has covered the entire cornea, or the changes may be most marked in the posterior segment of the globe. The progress of this disease is extremely slow, and in its early stage we are quite likely not to be able to distinguish it from the ordinary variety of scleritis. ‘The prognosis is bad; the blind eye usually has to be enucleated on account of pain. One eye alone has suffered in most cases, but in three that have been reported both eyes were practically blinded, and in two others the second eye was affected mildly. Little is known of the causation of scleritis. It has been ascribed at various times to rheumatism, gout, tuberculosis, gonorrhea by metastasis, syphilis, and menstrual disorders, but in most cases we are not able to find a definite cause. It is ordinarily thought to occur mainly in adults who are younger than those who are victims to episcleritis, but Derby found that ten of the sixteen patholog- ically examined cases of brawny scleritis occurred in patients be- tween sixty and eighty years of age, the youngest was thirty-four, the oldest seventy-six. Children do not seem to be subject to scleritis. THE SCLERA 197 Episcleritis When we see a circumscribed, reddish, ‘elevated spot with a rather yellowish center and a lilac or violet periphery, which appeared suddenly, the question is whether it is a phlyctenule, or a nodule produced by an episcleritis. In neither case is there apt to be much irritation of the eye, photophobia, lacrimation, or any circum- corneal injection, yet, as a rule, the differentiation is easy. Phlyc- tenular conjunctivitis is seldom seen except in childhood, while epi- scleritis is a disease of adult life. A phlyctenule causes no pain and is not tender, while an episcleritis is apt to be attended by a dull pain, and the affected part of the globe is tender to the touch. The conjunctiva immediately surrounding it is hyperemic in either case, but if we move it back and forth we can see that a phlyctenule and all of the redness moves with it, while an episcleral nodule remains fixed, together with the lilac or violet vessels, and allows the conjunctiva to slide over it. A drop of adrenalin solution blanches the conjunctival vessels quickly, but does not affect the deep, episcleral ones so readily. If there have been former attacks a history of obstinacy, and the presence of one or more grayish spots in the sclera, may decide the question in favor of episcleritis. A phlyctenule is transient and soon breaks down, while an epi- scleral nodule seldom changes after the first day or two, but per- sists for weeks and never ulcerates. ‘The nodule finally becomes absorbed, and either leaves no trace, or a little gray spot, this de- pending on the depth to which the sclera has been invaded. Recur- rence is the rule, but the same spot is never attacked twice. Episcleritis varies in severity and, though it does not induce the destructive lesions characteristic of deep scleritis, it may be attended by iritis, or by a sclerosing keratitis when it occurs close to the cornea. Sometimes a slight, diffuse episcleritis is to be observed in interstitial keratitis. The cause of a typical recurrent episcleritis is obscure. It is most apt to be met with in middle aged or elderly people, though occasion- ally it is seen in younger adults, and frequently is ascribed to rheu- matism or gout. Sometimes arteriosclerosis, chronic nephritis, and diabetes have been believed to be responsible. Similar nodules are to be seen in leprosy, and occasionally in syphilis, but they are not apt to recur in these diseases. Primary tuberculosis of the sclera is questionable, according to Parsons, though the disease may ex- tend to it from the uvea. 198 . DIAGNOSIS FROM OCULAR SYMPTOMS Episcleritis Periodica Fugax Occasionally we meet with a case in which the patient has a circumscribed deep hyperemia of the episcleral vessels, over which the conjunctiva is congested, so that a little red spot is formed on the white of the eye, which is not associated with any noticeable swelling, lasts a few days, and recurs at intervals. Such a spot with such a history marks the mildest form of episcleritis. It is differentiated readily from a subconjunctival hemorrhage by the presence in it of distinct vessels, and from a phlyctenule by the congestion of the episcleral vessels and the absence of any little nodule. THE ANTERIOR CHAMBER » As we glance through the cornea we need to note the depth of the anterior chamber, any irregularities that may be present, the condition of the aqueous, and any collection of pus, blood, or exudate that it may contain. An adhesion of the iris to the cornea will cause one part of the chamber to be shallow, but when one part is much shallower than another, and this is not accounted for by such an adhesion of the iris, we look at once at the pupil, for if this is large and oval we have good reason to fear that a trans- parent lens has been dislocated partially into the anterior chamber. - An isolated shallow place may indicate the presence of an exudate, a tumor, or a foreign body in or behind the iris. If a circular protrusion of iris surrounds the pupil, while the margins of the latter are bound down to the anterior capsule of the lens, we have a crater pupil, which will be described later. We can perceive at once a very great deviation from the normal depth of the anterior chamber, but sometimes it is difficult to be sure of a slight, or even of a moderate variation. We must not pronounce upon it too quickly, for the depth of the chamber varies physiologically, not only with the size and length of the eyeball, but also at different periods of life in the same individual. It is shallow in early life, deeper in the adult, and becomes shallow again as age advances, but practically it is always the same in the two eyes, unless these differ widely in other respects. When only one eye is diseased a comparison of the two by oblique illumination will inform us in most cases whether its anterior chamber is ab- THE ANTERIOR CHAMBER 199 normally shallow or deep, but when both eyes are affected we may still be in doubt. Obliteration of the Anterior Chamber When the iris and lens are in apposition with the posterior sur- face of the cornea, or are separated from it by so minute a quantity of aqueous that it cannot be perceived, we say that the anterior chamber is absent, or has been obliterated. Unless the cause is plain we test the tension at once, for if this is subnormal we may be sure that an aperture exists through which the aqueous is escaping, while if it is above normal it is evident that the iris and lens have been driven forward by pressure within the eye itself. An external aperture may have been formed by a wound, or by the perforation of an ulcer, when we do not have to search for the cause, as a rule. Yet sometimes we find an empty anterior chamber in a patient who gives a history of a sudden blurring of vision, perhaps after a sharp pain in the eye, but none of any lasting pain, traumatism, operation, or severe inflammation, and then it will not be surprising if we find that an indolent ulcer has perforated. It is also possible, though by no means common, for a wound to have evacuated the chamber without attracting the attention of the patient in any other way. An anterior chamber that remains empty for more than a few hours indicates that healing of the opening is delayed and that a fistula is being formed. Sometimes we meet with such a delay after a cataract extraction, or an iridectomy, and then it commonly is due to the presence in the wound of a bit of iris, anterior capsule, or fibrin, which holds the lips of the wound apart. In other cases an anterior chamber may be seen to reform partially and then to disappear again repeatedly; the cause of this is that the aperture closes with a cicatrix which is so feeble that it ruptures as soon as the intraocular tension has reached a certain height. Shallow Anterior Chamber An anterior chamber that persists in remaining shallow after a cataract extraction, or an iridectomy, when the wound shows no delay in union, probably indicates a detachment of the choroid, which will soon be replaced. If it is associated with an oedematous swell- ing of the conjunctiva about the wound, the cicatrix contains a 200 DIAGNOSIS FROM OCULAR SYMPTOMS fistula through which aqueous is escaping into the subconjunctival tissue. Ordinarily we find the tension subnormal in both of these cases, but should it be normal or elevated, we inquire into the pos- sibility that a trephine operation has been performed for glaucoma. When the tension is above normal we find glaucoma in the majority of cases, but the same condition may be caused by a tumor, an exudate, or a hemorrhage in the back part of the eye. The differentiation has to be made from the history and the accompany- ing symptoms, and it may be easy or very difficult. When the media are clear we ought to be able to see a glaucomatous excava- tion of the papilla, and that the other possible causes are absent, or else detect these causes themselves; but when they are not clear the problem is not so simple. A history of blindness that pre- ceded the onset of pain, and a mass behind the lens, may indicate an intraocular growth; a preceding violent iridocyclitis that has blinded the eye and left it painful may lead us to suspect an exu- date; a history of traumatism, or the presence of blood in the aqueous may lead us to diagnose a hemorrhage; but the differen- tiation of an intraocular tumor from glaucoma, or from a post- lenticular exudate is by no means always easy. A flattened cornea also accounts for a shallow anterior chamber. Deep Anterior Chamber The anterior chamber is rendered unusually deep by such an abnormal curvature of the cornea as we find in keratoconus, kerato- globus, and infantile glaucoma. When we see a deep anterior chamber associated with a tremulous iris, we know that the lens has been either dislocated or removed. A deep anterior chamber associated with a ciliary injection and a number of dots on the lower part of the posterior surface of the cornea is symptomatic of cyclitis. Visible Changes in the Aqueous A reddish aqueous, or a hyphzema, shows the presence of blood. During a cataract extraction, or an iridectomy, blood may enter the anterior chamber from wounded vessels of the conjunctiva or iris, when it is of little consequence, as a rule, but if the hemorrhage should continue, or if it should recur in company with an irido- cyclitis, the prognosis is not very good. Spontaneous hemorrhages THE ANTERIOR CHAMBER 201 sometimes take place into the anterior chamber in cases of hemor- thagic glaucoma, intraocular tumors, leucocythemia, purpura, and hemophilia, and occasionally they accompany the onset of attacks of iritis. Other hyphemas are produced by traumatism. What- ever may be its cause, if a hyphema persists for a considerable time, its coloring matter may enter the cornea and cause a blood stain. A cloudy aqueous, or an exudate or hypopyon at the bottom of the anterior chamber, directs our attention to the iris, whether any other tissue is inflamed or not. Hypopyon is a collection of pus cells which often contains no pyogenic microorganisms, when we have to call it sterile pus. In many cases of keratitis its for- mation seems to be due to the irritation of the iris by the toxines of the pyogenic organisms in the cornea which have diffused through the aqueous. When it is fluid it is bordered above by a horizontal line, and may be scattered by shaking the head, but when clotted it forms a mass at the bottom of the chamber with a convex upper margin while increasing, and a concave one while passing away. A growth in the anterior chamber with more or less transparent walls and clear contents is a cyst of the iris, which may be small, or so large as to nearly fill the entire chamber. An opaque growth comes from the iris and may be