SIMPLE IRITIS.
Causes. Symptoms: redness of sclera, in dogs, cats, birds, pigs, with a narrow zone of white next the cornea, red scleral vessels immovable, iris dull gray or brown, uneven, sluggish in response to light, synechia anterior or posterior, lens and capsule clouded or clear, pupillary margin uneven, myosis or midriasis, black cataract. Treatment: rest, dark stall or covering, head elevated, midriatics, cocaine, antiseptic puncture, purgation, leeches, seton, cooling astringent lotions, diuretics, for tension in convalescence iridectomy. In traumatic cases careful antisepsis.
This may come from any one or more of the causes of internal ophthalmia above named. The inflammation, however, concentrates itself on the iris so as to overshadow the disease in the adjacent organs.
The more distinctive symptoms are the redness of the sclerotic in unpigmented organs (swine, birds, dogs, cats), the redness increasing as it approaches the margin of the cornea but leaving a narrow white zone surrounding the edge. The red vessels on the sclerotic are not moved with the conjunctiva when the lid is moved over the front of the eye. The front of the iris is dull, grayish or brownish, it is thickened unevenly and very sluggish in response to light and darkness. Not infrequently it is adherent to the back of the cornea (synechia anterior) or to the front of the lenticular capsule (synechia posterior). The lens and its capsule may or may not be clouded, but if the interior of the vitreous can be seen it is found to be clear. The pupil is more or less uneven in outline and sometimes it is torn at its inner edge so as to form shreds and projecting tongues. Myosis (contraction of the pupil) or midriasis (dilatation) may be present. If the latter has been preceded by adhesion a portion of the uvea may remain attached to the lenticular capsule constituting black cataract. The lens or its capsule may become opaque, and a fibrinous membrane may form over the pupil.
Treatment. Rest for body and eye are essential. A dark stall, or a thick covering for the eye is desirable. The head should be kept moderately elevated to facilitate the return of blood. The pupil should be kept widely dilated to prevent adhesions to the lens. Sulphate of atropia 5 grs. to the oz. of water should be applied a few drops at a time, thrice a day, or as often as may be necessary to secure dilatation. In case the atropia fails to secure dilatation a 5 per cent. solution of cocaine should be dropped into the eye every three or four minutes for four or five times and then another application of atropia may be tried warm. Should it still fail and should there be indications of extra congestion and swelling of the iris or of excessive tension of the eyeball, relief may be obtained by puncturing the cornea. With the reduction of the tension the iris will often respond to the midriatic. Benefit may also be obtained from an active purgative, or the application of leeches in the vicinity of the eye.
Cooling astringent applications may be kept up over the eye, or warm antiseptic applications will often give great relief.
In obstinate cases the yellow oxide of mercury ointment may be applied as advised for internal ophthalmia.
Cooling diuretics may also be of essential advantage.
If, after a fair recovery the bulb remains unduly tense, iridectomy may be resorted to as a prophylactic measure for the future. An incision is made with a lancet close in front of the margin of the cornea, and the iris seized and withdrawn with a pair of fine forceps, and a portion snipped off with fine scissors. The eye and instruments must be rendered absolutely aseptic by carbolic acid and boiling water, and the antisepsis of the eye must be carefully maintained until the wound is healed. This tends to relieve congestion in the iris and to moderate the secretion in the anterior chamber, so that the former extreme tension does not recur. In making choice of the seat of the iridectomy a selection may be made which will do away with adhesions, or one that will expose a portion of the lens which is still transparent, and which may restore vision when obscured by a cataract.
In traumatic cases there should be extra care in maintaining a thorough antisepsis of the eye as the great danger is that of infective panophthalmitis. The injection of antiseptic liquids under the eyelids, and the covering of the eye with antiseptic cotton wool or with a soft rag wet with an antiseptic lotion are important factors in treatment.