Acute angle closure glaucoma

What it is

Glaucoma is an optic neuropathy in which the retinal sensitivity is reduced and the IOP is a risk factor. The aqueous outflow is reduced either by resistance of the trabecular meshwork, which is the open angle form, or by closure, which is the angle closure form, and the ganglion cell layer is lost through pressure or ischaemia. In acute angle closure glaucoma a shallow anterior chamber with pupillary block obstructs the drainage of the trabecular meshwork by the bulging iris. It is an ocular emergency.

Causes and risk

The risk factors are hyperopia, the small eye with a big lens whose large lens crowds the angle; age over 70 yr; female sex; a family history; Asian and Inuit descent; mature cataracts; a shallow anterior chamber; and anything causing pupil dilation, that is topical and systemic anticholinergics, stress and darkness, all of which are contraindicated.

How it presents

The onset is sudden, with a painful eye and a halo around light. The pain is severe and abrupt and is associated with headache, nausea, abdominal pain and vomiting. The examination shows unilateral ciliary congestion with conjunctival redness, a hazy cornea with corneal edema, a mid-dilated pupil that is fixed and poorly reactive, reduced vision and a high IOP.

The pattern of redness places the disease. Ciliary congestion, also called circumcorneal or limbal congestion, is caused by acute corneal pathology such as keratitis or epithelial defects, by acute uveitis, and by acute angle closure glaucoma. Generalized congestion belongs to conjunctivitis and to diffuse scleritis or episcleritis, and it also comes as a consequence of the ciliary causes, when it is called combined ciliary and generalized congestion. Sectoral redness belongs to nodular or focal scleritis or episcleritis and to an inflamed pterygium.

An infectious conjunctivitis generally does not cause severe pain, headache, or a decreased pupillary response. Scleritis or episcleritis may present with similar features, but the pupillary response may help differentiate them from glaucoma.