ESSENTIALS OF DIAGNOSIS
Older age group, particularly farsighted individuals.
Rapid onset of severe pain and profound visual loss with “halos around lights.”
Red eye, cloudy cornea, dilated pupil.
Hard eye on palpation.
Primary acute angle-closure glaucoma (acute angle-closure crisis) results from closure of a preexisting narrow anterior chamber angle. The predisposing factors are shallow anterior chamber, which may be associated with farsightedness or a small eye (short axial length); enlargement of the crystalline lens with age; and inheritance, such as among Inuits and Asians. Closure of the angle is precipitated by pupillary dilation and thus can occur from sitting in a darkened theater, during times of stress, following nonocular administration of anticholinergic or sympathomimetic agents (eg, nebulized bronchodilators, atropine for preoperative medication, antidepressants, bowel or bladder antispasmodics, nasal decongestants, or tocolytics), or, rarely, from pharmacologic mydriasis (see Precautions in Management of Ocular Disorders, below). Subacute primary angle-closure glaucoma may present as recurrent headache.
Secondary acute angle-closure glaucoma, which does not require a preexisting narrow angle, may occur in anterior uveitis, with dislocation of the lens, or due to various drugs (see Adverse Ocular Effects of Systemic Drugs, below). Symptoms are the same as in primary acute angle-closure glaucoma, but differentiation is important because of differences in management. Acute angle-closure glaucoma, for which the mechanism may not be the same in all cases, can occur in association with hemodialysis.
Patients with acute glaucoma usually seek treatment immediately because of extreme pain and blurred vision, though there are subacute cases. Typically, the blurred vision is associated with halos around lights. Nausea and abdominal pain may occur. The eye is red, the cornea cloudy, and the pupil moderately dilated and nonreactive to light. Intraocular pressure is usually over 50 mm Hg, producing a hard eye on palpation.
Acute glaucoma must be differentiated from conjunctivitis, acute uveitis, and corneal disorders (Table 7–1).
Initial treatment, regardless of mechanism, is reduction of intraocular pressure. A single 500-mg intravenous dose of acetazolamide, followed by 250 mg orally four times a day, together with topical medications that lower intraocular pressure is usually sufficient. Osmotic diuretics, such as oral glycerin and intravenous urea or mannitol—the dosage of all three being 1–2 g/kg—may be necessary if there is no response to acetazolamide. Definitive treatment depends on the mechanism.
In primary acute angle-closure glaucoma, once the intraocular pressure has started to fall, topical 4% pilocarpine, 1 drop every 15 minutes for 1 hour and then four times a day, is used to reverse the underlying angle closure. The definitive treatment is laser peripheral iridotomy (eFigure 7–28) or surgical peripheral iridectomy (eFigure 7–29). Cataract extraction is a possible alternative. If ...