Diseases of the Canine Conjunctiva

Conjunctivitis is inflammation of the conjunctiva and must be differentiated from hyperaemia of the conjunctiva or vascular engorgement of the epislcera and sclera (Nasisse 1986). Mechanical irritation such as foreign bodies or dacryocystitis should be considered in unilateral conjunctivitis (Martin 1973). Mild degrees of inflammation will result in epiphora due to irritation, but must be differentiated from blocking of the nasolacrimal duct (Martin 1973). More severe inflammation will cause excessive production of mucous from the conjunctival goblet cells (Martin 1973).

Acute bacterial conjunctivitis is characterized by purulent ocular discharge, moderate chemosis and reluctance to allow examination of the eye (Martin 1973). In chronic conjunctivitis there is frequently a decrease in the tear production, it is often difficult to determine if the tear deficiency or the conjunctivits is primary (Martin 1973). Artificial tears are an important adjunct in therapy of chronic conjunctivitis (Martin 1973). Bacterial conjunctivitis is frequently seen accompanying chronic pyoderma, seborrheic dermatitis, and otitis externa (Nasisse 1986).

In allergic conjunctivitis, pruritus caused by pawing results in swollen eyelids and a hyperaemic and swollen conjunctiva (Glaze 1991). Exfoliative conjunctival cytology may reveal eosinophils (Glaze 1991), but eosinophilia is rarely seen (Martin 1973). The allergen may be identified by skin testing (Glaze 1991). Systemic glucocorticoid-therapy is usually very effective (Glaze 1991).

Mycotic conjunctivitis must be considered in chronic conjunctivitis that is nonresponsive to antibiotic-corticosteroid treatment (Schmidt 1974). Trauma with vegetative matter may indicate possibility of a mycotic infection as in humans. The conjunctiva is thickened, rather dry and very hyperaemic; there may be involvement of the cornea resulting in focal white to yellow plaques (Martin 1973). Treatment is topically applied nystatin or amphotericin B (Martin 1973).

Canine distemper can cause a viral conjunctivitis with symptoms of chemosis, tear deficiency (Martin 1973). In Canine Distemper cytoplasmic inclusion bodies may be isolated on exfoliative cytology of the nictitating membrane (Ernø 1964). Adenovirus I and II may also cause conjunctivitis (Martin 1973). Neonatal conjunctivitis is usually bacterial in dogs, and may present before the eyelids open. The treatment is splitting of the palpebral fissure and topical antibitics (Nasisse 1986).

This page was authored by T. F. Evans October 2000.