Keratitis - an inflammation of a cornea of an eye.

Etiology, pathogenesis. Arises under influence exogenous (pneumococcuses, staphilococcuses, streptococcuses, a virus of herpes, an adenovirus, mushrooms, etc.) or endogenous (a tuberculosis, a lues, etc.) Infectious factors. Exogenous keratites can develop at conjunctivitises owing to disturbance of a delivery of a cornea because of a prelum of a regional vascular network a hydropic conjunctiva, toxic action of a conjunctival secret on a cornea and penetration into its tissue of the originator of disease. At minor defects of a cornea the originator of a keratitis can be the microbes allocated from a dacryocyst at dacryocystites, or microbes of a normal conjunctiva. The special and rare form of an exogenous keratitis is represented with a desiccation and a secondary becoming infected of a cornea in case of a lagophthalmia. Endogenous keratites are caused by hit in an eye hematogenic by the originator, toxic products of its vital activity and disintegration or there are owing to allergic reactions, disturbances of an exchange and a trophicity of a cornea at a lesion of trigeminal unit or the first branch of a trigeminal nerve and at avitaminoses.

Signs. A photophobia, a dacryagogue, a nictitating spasm, the expressed pericorneal or admixed injection, disturbance of a transparence of a cornea. In it there are infiltrates: punctual, nodous, linear, polymorphic, isolated or merged, limited or diffusive, superficial or deep. The cornea becomes dim, matte, rough. Vessels often develop in its tissues - superficial, going of a conjunctiva, and deep. Sensitivity of a cornea is lowered or is absent. Infiltrates completely resolve or on their place proof opacifications of various intensity are formed. The ulceration of a cornea is possible. The sharp dropping, sometimes full loss of tactile sensitivity of a cornea is marked. Neuralgic pains quite often join. The tubercular allergic inflammation of a cornea usually proceeds in the form of a keratitis: the limbus has grayish, translucent eminences - phlyctenas to which the fascicle of vessels approaches. At a dissimination of a tubercular infection the deep diffusive keratitis is observed - on a background of the widespread homogeneous opacification in deep layers of a cornea there are желтовато-grey small centers of-dense infiltration, deep vessels.