conjunctivitis(redirected from vernal catarrh)
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conjunctivitis(kənjəngtəvī`təs), inflammation or infection of the mucosal membrane that covers the eyeball and lines the eyelid, usually acute, caused by a virus or, less often, by a bacillus, an allergic reaction, or an irritating chemical. Commonly called pinkeye, mild conjunctivitis usually causes redness, discharge, and itching of the membrane. Conjunctivitis may also be associated with upper respiratory infection or with childhood diseases such as measles. Bacterial forms of the disorder, whether chronic or acute, are treated successfully with antibiotics, and although viral conjunctivitis will clear up on its own in 8 to 10 days, antibiotic eyedrops or ointments are often prescribed for most cases of the disease in order to prevent bacterial conjunctivitis. Trachomatrachoma
, infection of the mucous membrane of the eyelids caused by the bacterium Chlamydia trachomatis. Trachoma affects at least 86 million people worldwide. An estimated 1.
..... Click the link for more information. , though rare in the United States, is a severe conjunctivitis that can cause loss of vision. Another severe form of conjunctivitis is caused by the gonococcus bacterium and is usually associated with a genital infection. Conjunctivitis in newborn infants, called ophthalmia neonatorum, was a problem at one time; however, routine instillation of silver nitrate solution into the eyes of newborn infants has materially reduced the incidence of blindness.
inflammation of the conjunctiva.
Conjunctivitis is the most common eye disease. It may be exogenous or endogenous in origin; the former is more frequent. Exogenous conjunctivitis is caused by various microbes, including streptococci, staphylococci, the diphtheria bacillus, and gonococci. The Koch-Weeks bacillus and the Morax-Axenfeld diplococcus are specific for conjunctivitis. The cause is also often viral infection. In addition, the condition may result from mechanical irritation, such as by foreign bodies, from exposure to heat, ultraviolet and ionizing radiation, or chemical agents.
Endogenous conjunctivitides arise in the presence of systemic infections (measles, scarlet fever), inflammations of the nasopharynx or teeth, or diseases of the gastrointestinal tract or liver. There are also allergic conjunctivitides.
Conjunctivitis is classified as either acute or chronic, according to its course. Acute conjunctivitis is manifested by a purulent discharge from the eye and redness (hyperemia) of the palpebral and ocular conjunctivae and sometimes by punctate hemorrhages under the conjunctiva and conjunctival edema. In some cases the surface of the conjunctiva becomes rough, a result of the appearance in it of ridged formations, or follicles, and papillae. Chronic conjunctivitis shows moderate changes in the conjunctiva. Most notable are subjective sensations, such as a feeling of dust in the eye and photophobia. Conjunctivitis is treated with sulfanilamides and antibiotic eyedrops. Hormonal (corticosteroid) preparations are used in some cases. In cases with purulent discharge the eyes are irrigated with boric acid solution or with a weak solution of potassium permanganate.
L. A. KATSNEL’SON
Conjunctivitis in animals is most often observed as a symptom of various other diseases. The causes of independent conjunctivitides in animals may be mechanical, chemical, or radiant irritants or the causative agents of certain infectious diseases. The principal manifestation is conjunctival hyperemia. The condition is treated by eliminating the primary causes and using antiseptic solutions.
REFERENCESArkhangel’skii, V. N. Glaznye bolezni, 2nd ed. Moscow, 1969. Pages 124–33.
Mnogotomnoe rukovodstvo po glaznym bolezniam, vol. 2, book 1. Moscow, 1960. Pages 46–186.