Chronic superficial keratitis

Bedford, P. G. C. and Longstaffe, J. A., 1979, Corneal Pannus (chronic superficial keratitis) in the German Shepherd Dog, J. Small Anim. Pract, 20 41. 

Band keratopathy was first described in 1848 and is a chronic degenerative condition characterized by the deposition of calcium carbonate salts in the superficial corneal layers, most frequently in the interpalpebral area. Although there are many reported cases of idiopathic band keratopathy, some of which seem to have a hereditary component, the most common causes are associated with chronic ocular inflammation and systemic conditions resulting in altered calcium metabolism. Band keratopathy is typically seen in eyes with chronic uveitis, severe superficial keratitis, corneal ulcers, chemical burns, interstitial keratitis (IK), trachoma, phthisis bulbi, and prolonged glaucoma. The chronic anterior uveitis of juvenile idiopathic arthritis is frequently associated with band keratopathy, with one study reporting its development in 66% of patients with juvenile idiopathic arthritis. 

In its early stages trachoma presents as a chronic follicular conjunctivitis with a predilection for the superior tarsal and bulbar conjunctiva. Over time, the conjunctival reaction becomes papillary in nature and, with the inflammatory infiltration that occurs, the follicular character of the infection can become obscured. Patients experience symptoms of photophobia, tearing, and mucoid or mucopurulent discharge. Limbal edema and superior bulbar conjunctival hyperemia also may occur. Conjunctival follicles that form at the limbus are characteristic of severe trachoma. Primary corneal involvement often includes superior epithelial keratitis and superficial superior pannus formation. A wide variety of corneal infiltrates... 

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