—glaucomatous /glaw koh"meuh teuhs, -kom"euh-, glow-/, adj./glaw koh"meuh, glow-/, n.Ophthalm. abnormally high fluid pressure in the eye, most commonly caused either by blockage of the channel through which aqueous humor drains (open-angle glaucoma or chronic glaucoma) or by pressure of the iris against the lens, which traps the aqueous humor (angle-closure glaucoma or acute glaucoma).[1635-45; < Gk glaúkoma opacity of the eye lens. See GLAUC-, -OMA]
* * *Disease marked by increased pressure in the eye.A result of blockage of the flow of fluid (aqueous humour) at the outer edge of the iris, this pressure is transmitted to the optic nerve head and the retina. Chronic glaucoma can be treated with drugs that contract the pupil. Acute glaucoma may be intermittent. Permanent relief requires surgery to provide an outlet for the fluid. Either type causes vision impairment or blindness if untreated.
* * *disease caused by an increase in pressure within the eye as a result of blockage of the flow of aqueous humour, a watery fluid produced by the ciliary body. (The ciliary body is a ring of tissue directly behind the outer rim of the iris; besides being the source of aqueous humour, it contains the muscle that flattens the curvature of the lens for far vision.) The normal flow of the aqueous humour is (1) from the ciliary body into the posterior chamber, a narrow space bounded in front by the iris, on its outer side by the ciliary body, and in back by the lens and the vitreous body, a jelly-like substance that occupies a major part of the eyeball; (2) from the posterior chamber through the pupil into the anterior chamber, the space in front of the lens and the iris and in back of the transparent window formed by the cornea; and (3) from the anterior chamber through a sievelike layer of tissue in the lining of the eyeball at the outer periphery of the iris into a circular channel, the canal of Schlemm, from which the aqueous humour flows (by way of vessels called aqueous veins) into blood vessels. Blockage of the aqueous humour flow causes increased pressure in the posterior chamber, and this pressure is transmitted by way of the vitreous to the optic nerve head and the retina. Abnormally high intraocular pressure that is unrelieved causes vision impairment.There are two types of blockage that result in glaucoma. (1) The blockage may occur in the porous tissue between the anterior chamber and the canal of Schlemm, in the canal itself, or in the aqueous veins. This blockage is continuous, and the effect is chronic glaucoma. (2) In persons in whom the angle at the periphery of the anterior chamber is acute—i.e., in whom the outer rim of the iris is close to the wall of the eyeball—the pressure of aqueous humour upon the back of the iris may force the outer part of the iris against the wall, so as to cover the outlet into the canal of Schlemm. Glaucoma caused by this type of obstruction is called acute or narrow-angle glaucoma. When the pupil contracts, as during sleep, it tends to pull the iris away from the entrance into the canal of Schlemm and allow passage of aqueous humour, so that the high intraocular pressure may be intermittent in this type of blockage.Chronic glaucoma does not cause symptoms in its early stages, and it is diagnosed by observation of the abnormally high intraocular pressure or the physical effects of abnormal pressure upon the optic disk (the point where the optic nerve leaves the eyeball). Treatment is primarily medical—the reduction of intraocular pressure by means of drugs that contract the pupil (miotic drugs) and allow greater outflow of the aqueous humour.Narrow-angle glaucoma causes pain in the eye, headaches, and sometimes nausea and vomiting. The affected person may see halos around lights. Treatment of an acute attack is similar to that of chronic glaucoma, but permanent elimination of the high pressure requires surgery; i.e., an opening is cut through the iris at its outer periphery to allow passage of the aqueous humour.
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См. также в других словарях:
Glaucoma — Classification and external resources Acute angle closure glaucoma of the right eye. Note the mid sized pupil, which was nonreactive to light, and injection of the conjunctiva. ICD 10 … Wikipedia
glaucoma — m. oftalm. Enfermedad ocular que se caracteriza por un aumento de la presión intraocular, dureza del globo ocular, alteraciones del campo visual y atrofia de la papila óptica. Suele estar provocada por una producción excesiva de humores oculares… … Diccionario médico
glaucoma — 1640s, from Gk. glaukoma cataract, opacity of the lens (cataracts and glaucoma not distinguished until c.1705), from OMA (Cf. oma) + glaukos, an adj. of uncertain origin (see GLAUCOUS (Cf. glaucous)) … Etymology dictionary
glaucoma — (Del lat. glaucōma, y este del gr. γλαύκωμα, der. de γλαυκός, verde claro, por el color verdoso que toma la pupila en esta afección). m. Med. Enfermedad del ojo, caracterizada por el aumento de la presión intraocular, dureza del globo del ojo,… … Diccionario de la lengua española
Glaucoma — Glau*co ma, n. [L., fr. Gr. glay kwma, fr. glayko s light gray, blue gray.] (Med.) Dimness or abolition of sight, with a diminution of transparency, a bluish or greenish tinge of the refracting media of the eye, and a hard inelastic condition of… … The Collaborative International Dictionary of English
Glaucōma — (Med.), s. Glaukom … Pierer's Universal-Lexikon
Glaucoma — vgl. Glaukom … Das Wörterbuch medizinischer Fachausdrücke
glaucoma — |ô| s. m. Endurecimento do globo ocular, por excesso da tensão interna, que provoca uma diminuição da visão e dores de cabeça … Dicionário da Língua Portuguesa
glaucoma — sustantivo masculino 1. (no contable) Área: medicina Enfermedad ocular que se caracteriza por un aumento de la presión dentro del ojo y la atrofia de la retina … Diccionario Salamanca de la Lengua Española
glaucoma — ► NOUN Medicine ▪ a condition of increased pressure within the eyeball, causing gradual loss of sight. ORIGIN Greek glauk ma, from glaukos bluish green or grey (because of the grey green haze in the pupil) … English terms dictionary
glaucoma — [glô kō′mə, gloukō′mə] n. [L < Gr glaukōma < glaukos (see GLAUCO ) + OMA] any of a group of related eye disorders characterized by increased pressure within the eye which impairs the vision and may slowly cause eye damage and total loss of… … English World dictionary