Keratitis(redirected from microbial keratitis)
Also found in: Dictionary, Thesaurus, Medical.
inflammation of the cornea of the eye.
Keratitis arises from certain external, predominantly infectious, factors (exogenic keratitis) or from common systemic diseases (endogenic keratitis). Keratitis may also be caused by mechanical, thermal, chemical, or radiation traumas, as well as certain types of vitamin deficiency. Keratitis is manifested by photophobia, epiphora, pain, and redness of the eye, by edema of the cornea and disruption of its transparency (development of an inflammatory infiltrate), and sometimes by loss of sensitivity of the cornea and the appearance of newly formed ingrown blood vessels. The duration and course of keratitis depends on the cause of the inflammation; with infectious keratitis it depends on the type and virulence of the microorganisms and also on the reactivity and condition of the body. Often as a result of keratitis there remain persistent opacities (cataracts), in some cases small and unobtrusive and in others large and intense, which are often the cause of a decrease in vision, especially if they are located in the central, contrapupillary portion of the cornea.
A distinction is made between surface keratites and deep keratitis. The most frequently encountered of the surface exogenic keratites are catarrhal keratitis, which develops from infectious conjunctivitis; herpetic keratitis, the result of viral affection of the eye; keratitis with epidemic adenoviral conjunctivitis; serpiginous corneal ulcer, a serious purulent disease usually caused by a pneumococcal infection and often arising after minor injury to the cornea (the entry of small foreign bodies or scratches); and keratitis with blennorrhea, diphtheria, or trachoma.
Most frequently encountered of the surface endogenic keratites is phlyctenular keratitis as a manifestation of an allergy in children and adolescents with tubercular intoxication; keratitis in this form is usually bilateral and tends to recur. The typical form of deep endogenic keratitis is parenchymatous keratitis with congenital syphilis; it is observed in children and adolescents, is as a rule bilateral, and is characterized by a prolonged course and diffuse infiltration of the cornea, often with ingrown blood vessels; vision, which decreases severely in the beginning, may subsequently improve substantially or even be restored with resorption of infiltrates. Deep keratitis with tuberculosis usually affects one eye and leaves intense opacity of the cornea.
Treatment of keratitis must be directed toward eliminating the cause of the disease; with infectious keratites antibiotics or sulfanilamides are used locally; with cataracts that substantially decrease vision surgical intervention (keratoplasty) is necessary.
REFERENCEBarbel’, I. E. “Bolezni rogovoi obolochki.” In Mnogotomnoe rukovodstvo po glaznym bolezniam, vol. 2, book 1. Moscow, 1960. (Bibliography.)
M. L. KRASNOV