In the milder forms of the affection there may be little or no hyperthermia, while in severe attacks the febrile reaction may be considerable.
Lesions. The non-traumatic cases which are not complicated by varied wounds and injuries, show exudation and cell proliferation in the palpebral conjunctiva and to a less extent in the bulbar. The conjunctival papillæ are swollen and become visible to the naked eye and in aggravated cases stand out like fungous masses. The superficial layer of cylindroid epithelium is found swollen, opaque and sometimes desquamating. The lymphoid bodies which are most abundant in the depth of the conjunctival sac, are infiltrated, swollen, and bulging in reddened masses.
Other lesions in the nature of granular or follicular hyperplasia, abscess and corneal new growth and ulcers may follow, but will be better considered under separate headings.
The tendency of simple uncomplicated conjunctivitis is to recovery which may be completed in a week or ten days. In case of contused wounds, abscess, ulcer, special infection in a lymphatic subject like the ox, the affection is more likely to be prolonged or followed by grave lesions.
Treatment. The first object must be to remove the cause, hence foreign bodies, displaced lids or cilia, irritant gases, excess of light, cold draughts or exposure, etc., must be sought and corrected. For the removal of the foreign bodies, fine forceps or various common articles (hair pin, lead pencil, a pin head, a folded clean handkerchief, or even the clean finger) may be used. In case of wounds especially, they should be first sterilized. Boiled water which has been cooled to luke warm may be used from a sterilized syringe.
Locally antiseptic and astringent collyria (sublimate solution—1:5000), zinc sulphate—1:1000, lead acetate, alum, tannin, silver nitrate, etc., are valuable and may even be thrown under the eyelids from a syringe with a finely rounded nozzle and many orifices. Even a 2 per cent. solution of silver nitrate may be applied in the conjunctival sac twice daily, or as being less irritating, a solution of pyoktannin (1:1000). If the irritation is great a soft rag wet with the solution may be attached to the headstall of the bridle and hung loosely over the eye, care being taken to prevent drying. A few grains of morphia added to the collyria will be specially soothing. Irrigation of the eyelids or bathing for ten or fifteen minutes at a time with luke warm water, will often greatly relieve. When the eyelids become agglutinated during sleep or prolonged closure, as in the small animals, cleanse with a tepid sublimate solution, and smear with vaseline. In severe cases local depletion may be resorted to. The hair may be shaved off from an area of 2 inches below the orbit, and a cup applied for ten minutes. Scarification may or may not be resorted to. Or a leech may be applied to the same part.
A laxative often proves an excellent derivative especially useful in costive conditions.
CHRONIC CONJUNCTIVITIS.
Sequel of acute. Same causes. Old horses, young foals, damp lands, night dews, frosts, eczema, follicular scabies. Lesions: swelling of lymph bodies in conjunctival pouch, general congestion, chemosis, hypertrophied papillæ, clouded cornea; Symptoms: as in acute form but less intense. Treatment: Remove cause, irritants, damp soils, stables, etc., glare of light, heat, etc., astringent antiseptic lotions, atropia, mercury oxide, counter-irritation, setoning, cupping, leeching.
This is generally recognized by veterinary writers as a sequel of the acute form, though it may begin de novo, from slight persistent causes of irritation. Habitual exposure to fierce light, dusty roads, ammoniacal and other gaseous emanations, and at other times to the dust from musty fodders in a high rack, trichiasis, entropion, ectropion, and indeed any continued irritation may start the disease or keep it up. Leblanc says it is especially common in old horses and young foals pastured on low damp grounds, bottom lands and lake shores, and in worn out work oxen which have been exposed to cold night dews, or frosts. In this respect it resembles the recurring ophthalmia of the horse which prevails especially in lymphatic subjects. In dogs, Leclainche has observed it associated with eczema or follicular scabies of the lids.