What is the diagnosis and treatment for Acute Angle-Closure Glaucoma?

From the Guidelines

Acute angle-closure glaucoma is a serious eye emergency requiring immediate medical attention, and treatment should begin with medications to rapidly lower intraocular pressure, followed by definitive treatment with laser peripheral iridotomy as soon as possible, as recommended by the most recent guidelines 1.

Key Considerations

• The initial treatment of acute angle-closure glaucoma (AACC) aims to lower intraocular pressure (IOP) to relieve acute symptoms and prevent further damage, with medical therapy usually initiated first to reduce pain and clear corneal edema 1.
• Medical therapy may include topical beta-adrenergic antagonists, topical alpha2-adrenergic agonists, topical, oral, or intravenous carbonic anhydrase inhibitors, topical parasympathomimetics, and oral or intravenous hyperosmotic agents, with the choice of agents depending on the patient's overall physical and medical status 1.
• Laser iridotomy is the preferred surgical treatment for AACC, as it has a favorable risk-benefit ratio and can relieve pupillary block, prevent or retard the formation of peripheral anterior synechiae (PAS), and result in significant angle widening and iris-profile flattening 1.

Treatment Approach

• Treatment should be initiated promptly, with the goal of lowering IOP to reduce pain and prevent further damage to the optic nerve, trabecular meshwork, iris, lens, and cornea 1.
• The fellow eye of a patient with AACC should be evaluated and considered for prophylactic laser iridotomy, as it is at high risk for a similar event, with approximately half of fellow eyes developing AACC within 5 years 1.
• Chronic parasympathomimetic therapy is not an appropriate alternative for prophylaxis of the fellow eye or treatment of established angle closure, and it is not a substitute for iridotomy 1.

Important Considerations

• The configuration of the iris becomes less bowed with pupillary constriction, and treatment using parasympathomimetics may open the angle, but miotic therapy is frequently ineffective when the IOP is markedly elevated due to pressure-induced ischemia of the pupillary sphincter 1.
• Systemic hyperosmotic agents may need to be used to achieve a rapid decrease in IOP in the setting of AACC, and corneal indentation performed with a four-mirror gonioscopic lens, cotton-tipped applicator, or tip of a muscle hook may help break pupillary block 1.

From the FDA Drug Label

For adjunctive treatment of: ... preoperatively in acute angle-closure glaucoma where delay of surgery is desired in order to lower intraocular pressure. The preferred dosage is 250 mg every four hours, although some cases have responded to 250 mg twice daily on short-term therapy In some acute cases, it may be more satisfactory to administer an initial dose of 500 mg followed by 125 or 250 mg every four hours depending on the individual case.

Acetazolamide is used for the treatment of acute angle-closure glaucoma. The dosage is 250 mg every four hours or 250 mg twice daily on short-term therapy, and in some cases, an initial dose of 500 mg followed by 125 or 250 mg every four hours may be more satisfactory 2 2.

From the Research

Definition and Treatment of Acute Angle Glaucoma

• Acute angle glaucoma is a type of glaucoma where the flow of aqueous humor is obstructed, leading to a sudden increase in intraocular pressure 3.
• The goal of treatment for acute angle-closure glaucoma is to reduce intraocular pressure quickly with medications or surgery, then prevent the recurrence of the obstruction to aqueous flow by a definitive ophthalmologic procedure 3.

Management of Acute Closed-Angle Glaucoma

• A study published in 1979 investigated the hypotensive effect of intramuscular or intravenous acetazolamide with frequent instillation of pilocarpine, and the hypotensive effect of topical timolol alone and together with pilocarpine in the treatment of acute closed-angle glaucoma 4.
• The results showed that there was no marked difference in the hypotensive effect whether pilocarpine was used frequently or in a single dose, in different concentrations, or in different vehicles after acetazolamide 4.
• Topical timolol alone was not effective enough to control the intraocular pressure in acute closed-angle glaucoma, but a good hypotensive effect was seen when topical timolol was followed by pilocarpine 4.

Comparison of Treatments for Acute Primary Angle Closure

• A randomized controlled trial published in 2004 compared the effect of brimonidine and timolol in reducing visual field loss in patients with acute primary angle closure (APAC) 5.
• The results showed that there was no difference between the two groups in terms of the number of patients with progressing locations, the mean number of progressing locations per subject, or the mean slope of the progressing locations 5.
• Another study published in 2019 found that both brimonidine and timolol improved the mean deviation slopes in patients with open-angle glaucoma 6.

Medications for Glaucoma Treatment

• Prostaglandin analogues (PGAs) are frequently used as first-line monotherapy for primary open-angle glaucoma, due to their efficacy and low risk of systemic side effects 7.
• PGA-based fixed combinations are also used in patients who progress or fail to achieve the target intraocular pressure 7.
• Timolol is often used in combination with other medications, such as pilocarpine or brimonidine, to control intraocular pressure in glaucoma patients 4, 5.