glaucoma

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glaucoma

(glôkō`mə), ocular disorder characterized by pressure within the eyeball caused by an excessive amount of aqueous humor (the fluid substance filling the eyeball). This causes pressure against the optic nerve and compression of the blood vessels of the eye—the resulting impairment of vision ranges from slight abnormalities to total blindness. Chronic open-angle glaucoma is the result of impeded drainage of aqueous humor. In acute angle-closure glaucoma, the anterior chamber of the eye is shallower and the iris may obstruct the meshwork at the entrance of the canal of Schlemm. Although glaucoma is a leading cause of blindness in the United States, with timely treatment blindness is almost always avoided.

Chronic glaucoma begins gradually over a period of months or years, usually in patients over the age of 40. There are no symptoms in the early stages, and the condition can be detected only by measurement of the intraocular pressure. Such an examination is recommended every three years for all persons over the age of 20. As the disease progresses, often the only symptom is a gradual loss of peripheral vision. Chronic glaucoma can usually be controlled with eye drops or pills that increase the outflow or decrease the production of aqueous humor; laser treatment is also effective in the early stages. If treatment is continued throughout life, useful vision will be preserved in most cases; untreated individuals will gradually become blind.

Acute closed-angle glaucoma, which accounts for only 10% of the incidence of the disease, begins abruptly with severe pain and blurred vision. It is a medical emergency that causes permanent blindness in two to five days if left untreated. Surgery is usually necessary.

Glaucoma

 

(also called “yellow water” or “green water” in Russian—in glaucoma the region of the pupil sometimes begins to gleam with a yellowish gray or bluish gray light), a disease of the eyes, the principal symptom of which is an increase in intraocular pressure with a reduction of vision.

Intraocular pressure in glaucoma sometimes reaches 80 mm of mercury, or 10.67 kilonewtons (kN)/m2. (Normal pressure is 18-27 mm of mercury, or 2.4-3.6 kN/m2.) The pressure in the eye may rise spontaneously (primary glaucoma) or as the result of a previous or current disease of the eye (secondary glaucoma). The underlying cause of the disease is a disruption of the circulation of intraocular fluid—most commonly, difficulty in its drainage. Glaucoma usually develops in the elderly, often affecting both eyes, and as a rule proceeds chronically; in the absence of systematic treatment it is progressive. Glaucomas may be defined as either congestive (narrow angle), characterized by periodic clouding of vision, rainbowed halos around a light source, and a sensation of pressure in and around the eye, simple (open angle), in which these subjective phenomena are absent. In any form of glaucoma visual acuity gradually diminishes, the field of vision becomes limited, and the optic nerve atrophies. An acute attack of glaucoma, characterized by an abrupt rise in intraocular pressure, may develop at any stage of the disease; severe pains in and around the eye develop, there is reddening of the eyes, edema and clouding of the cornea, dilatation of the pupil, and reduction of vision, sometimes to the point of blindness. There is often accompanying nausea and vomiting. Glaucoma is the most common cause of blindness. The treatment may be medical or sometimes surgical. In the USSR prevention consists of examination of persons over 40 years of age and treatment of patients with established glaucoma at out-patient prevention and treatment clinics. Prevention of blindness from glaucoma involves early diagnosis of the disease and systematic treatment.

REFERENCES

Averbakh, M. I. “Glaukoma.” In Oftalmologicheskie ocherki. Moscow, 1949.
Mnogotomnoe rukovodstvo po glaznym bolezniam, vol. 2. [Edited by V. N. Arkhangel’skii.] Moscow, 1960.

M. L. KRASNOV

glaucoma

[glau̇′kō·mə]
(medicine)
A disease of the eye characterized by increased fluid pressure within the eyeball.

glaucoma

a disease of the eye in which pressure within the eyeball damages the optic disc, impairing vision, sometimes progressing to blindness
References in periodicals archive ?
However, because of the nature of the anatomic relationships of the structures surrounding the posterior chamber, the degree of relative pupillary block necessary to induce angle closure is less than that in pure pupillary block angle closure glaucoma [2].
Anatomical basis for primary angle closure glaucoma.
Right and left eye acute angle closure glaucoma was diagnosed and all medications were rechecked dopamine and adrenaline infusions and nebulized agents were stopped.
115) in mean age of angle closure glaucoma subjects 54.
Topical mitotics are contraindicated as a method of treatment and can worsen the condition since the angle closure glaucoma, in this case is not pupil block related.
The Baltimore eye survey of 4870 people found no cases of acute angle closure glaucoma precipitated by mydriatics11.
Keeping these aspects in view, the present study aims to study primary angle closure glaucoma with respect to its presentation, management with Nd:YAG laser iridotomy and post laser complications.
Bilateral acute angle closure glaucoma after administration of paroxetine.
Theoretically, anticholinergics and antiadrenergics which have high dose antipsychotics (such as phenothiazine) should be foreseen that they might form a risk factor in terms of angle closure glaucoma (ACG) Actually, when antipsychotics are compared with the tricyclic antidepressants (TCAs), they relatively have less effects on ocular smooth muscles and risk of producing ACG is far less in proportion to TCA.
Indentation gonioscopy can also be performed with the 4-mirror lens and is a useful technique for assessing angle closure glaucoma.
Phacomorphic is more often encountered in clinical practice and presents as an angle closure glaucoma due to pupillary block.
Outcome of laser peripheral iridotomy in chronic primary angle closure glaucoma.