Approach

The American Academy of Ophthalmology supports the prompt and appropriate referral of individuals to an ophthalmologist when they present with intraocular pressure at an abnormal level, transient or sustained loss of any part of the visual field, or a family history of glaucoma (especially if the patient is of African or Hispanic origin).[38]

Initial medical management of acute episode

The immediate goal of treatment is to relieve the acute symptoms, decrease intraocular pressure (IOP), and clear corneal edema.[17] This is usually achieved with medical therapy.[17][24] Oral, topical, or intravenous carbonic anhydrase inhibitors, topical beta-blockers, and topical alpha-2 adrenergic agonists lower IOP through suppression of aqueous humor production.[17] Beta-blockers reduce IOP by around 20% to 25%.[37] Alpha-agonists reduce IOP by around 18% to 35%.[37] Carbonic anhydrase inhibitors, topical beta-blockers, or alpha-2 adrenergic agents may be used as first-line therapies either alone but more typically in combination.

In patients in whom angle closure is thought to be secondary to pupillary block or plateau iris syndrome, cholinergic agents (such as pilocarpine) should be started after IOP decreases to <40 mmHg.[37] They can paradoxically result in shallowing of the anterior chamber and narrowing of the angle in eyes with angle closure secondary to lens-induced mechanism or aqueous misdirection (malignant glaucoma). They are therefore contraindicated in these cases.[39] Corneal indentation may help break pupillary block.[17]

If these medical treatments are unsuccessful, hyperosmotic agents should be used. Hyperosmotic agents are also used initially when pressures are exceedingly high.[17]

Following resolution of the acute attack, definitive surgical treatment should be performed within 24 to 48 hours with the aim of achieving a persistently open angle.

Initial surgical management of acute episode

If the IOP cannot be decreased with medical therapy, an anterior chamber paracentesis can offer immediate resolution. This often results in the clearing of corneal edema, which can make performing a laser peripheral iridotomy easier. A study showed that this may also benefit the outcomes of eventual surgical intervention.[40] This prospective trial randomized patients to receive either paracentesis at presentation or no paracentesis at presentation, with both groups going on to have surgery (trabeculectomy). Paracentesis reduced IOP significantly in all patients, without serious adverse events. Post-trabeculectomy inflammation was seen in fewer eyes and at a lower level in the paracentesis group. In addition, the percentage of functional filtration blebs, success rate of trabeculectomy, and the rate of visual recovery were statistically significantly higher in the paracentesis group. This study supports the acute lowering of IOP with paracentesis upon presentation of acute angle-closure glaucoma, and suggests a benefit in the long-term success of trabeculectomy in these patients.

Definitive surgical management for chronic ACG and after resolution of acute attack

Definitive treatment is aimed at achieving a persistently open angle.

Laser peripheral iridotomy (LPI), where a laser is used to make an opening in the iris, is usually successful for acute angle-closure glaucoma.[17][41][42][43][44]​​

LPI alleviates pupillary block by allowing aqueous humor to bypass the pupil. The pressure differential between anterior and posterior chambers is eliminated, and the iris loses its convex configuration and falls away from the trabecular meshwork (TM), resulting in opening or widening of the angle.[42][43][45][46][47] LPI is indicated in all eyes with primary angle closure and usually in fellow eyes as well, because the majority of fellow eyes will also develop glaucomatous changes.[24][48][49][50][51] An untreated fellow eye has a 40% to 80% risk of developing an acute attack. Therefore, it is recommended that the contralateral eye be treated prophylactically with laser peripheral iridotomy if the chamber angle is found to be anatomically narrow.[17][24][49][50][51]

Factors associated with persistent angle closure after LPI include narrower angle, thick iris, an anteriorly positioned ciliary body, and a greater lens vault.[52]

Laser iridoplasty (also known as gonioplasty) can be considered in the presence of a patent LPI with a residual appositional angle. In this procedure, an argon laser is used to place contraction burns in the peripheral iris over its entire circumference in order to pull the peripheral iris away from the TM.[53]

If residual angle closure is attributable to the lens, then lens extraction surgery with or without goniosynechialysis is considered.[54][55][56][57][58]

Cholinergic agents may be used if there is residual angle closure after laser treatment. These agents cause pupil constriction with thinning of the iris and its pulling away from the inner eye wall and TM, thus opening the angle.

Persistently elevated IOP in patients with ACG despite surgery

If IOP remains elevated following these measures in acute angle-closure glaucoma, as well as in cases of chronic angle-closure glaucoma, it is lowered in a fashion similar to open-angle glaucoma with IOP-lowering medications, and if these are ineffective, then IOP-lowering surgery.[17][59]

Topical ophthalmic prostaglandin analogs work by increasing uveoscleral outflow. They reach peak effectiveness 8 to 12 hours after administration, so they are not used during acute attacks.[37] However, as chronic therapy, they are the most potent IOP-lowering agents available and should be used first line.[60][61] Topical beta-blockers and alpha-2 adrenergic agonists may also be used. They are typically used alone or in combination at the discretion of the physician.

Systemic carbonic anhydrase inhibitor chronic therapy is uncommonly used because of the many adverse effects of chronic systemic use, and should be reserved for patients with glaucoma refractory to other medical treatment.[37]

Uncommonly IOP remains elevated despite all these measures, and in this case IOP-lowering surgery, such as trabeculectomy or aqueous tube shunt implantation, is indicated.[62][63] [ Cochrane Clinical Answers logo ] [ Cochrane Clinical Answers logo ]

Repeat episode of acute ACG

If the mechanism of angle closure has not been eliminated, an acute episode can recur. In this case the clinician should look for the specific mechanism of angle closure and treat it accordingly. It is also important in such cases to verify that the peripheral iridotomy is patent.

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