Angle-closure glaucoma

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

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]

The goals of treatment are to reverse or prevent angle-closure, to control intraocular pressure (IOP), and to prevent damage to the optic nerve.[1]

Initial medical management of an acute episode of angle-closure glaucoma

Management of an acute episode necessitates lowering potentially harmful high IOP to relieve pain and reduce pain and corneal oedema.[1]

Topical or systemic carbonic anhydrase inhibitors, topical beta-blockers, and topical alpha-2 agonists may be used as first-line therapies alone, but more typically in combination. These drugs lower IOP through suppression of aqueous humour production.[1] Topical beta-blockers reduce IOP by approximately 20% to 25%.[39] Topical alpha-2 agonists reduce IOP by approximately 18% to 35%.[39]

In patients in whom angle closure is thought to be secondary to pupillary block or plateau iris syndrome, topical cholinergic agents (e.g., pilocarpine) should be started after IOP decreases to <40 mmHg.[39] Cholinergic agents are contraindicated in angle closure secondary to a lens-induced mechanism or aqueous misdirection; they can, paradoxically, result in shallowing of the anterior chamber and narrowing of the angle in these eyes.[17] Corneal indentation may help break pupillary block.[1]

Systemic hyperosmotic agents should be used if the above medical treatments are unsuccessful. Hyperosmotic agents are also used initially when pressures are exceedingly high.[1]

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 of angle-closure glaucoma

If the IOP cannot be decreased with medical therapy, an anterior chamber paracentesis can offer immediate resolution.[40][41] This often results in the clearing of corneal oedema, which can make performing a laser peripheral iridotomy easier.[41]

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

Definitive treatment is aimed at achieving a persistently open angle and alleviation of pupillary block. The preferred treatment is laser peripheral iridotomy (LPI).[1][39] LPI should be performed in the fellow eye when indicated (i.e., if the chamber angle is found to be anatomically narrow).[1]

One meta-analysis of two randomised controlled trials found that eyes treated with iridotomy (where a laser is used to make an opening in the iris) had wider angles at 1 and 5 years compared with eyes that received no iridotomy.[42] Eyes undergoing iridotomy experienced fewer peripheral anterior synechiae (PAS) at 5 years than eyes that received no iridotomy.[42] The effects of iridotomy on eye pressure and vision were: however, limited. Of note, studies included in the meta-analysis enroled patients at risk of developing primary angle-closure glaucoma (PACG), rather than patients with PACG.

Factors associated with persistent angle closure after LPI include narrower angle, thick iris, an anteriorly positioned ciliary body, and a greater lens vault.[43] If the iridotomy becomes occluded, pupillary block may recur, and repeat iridotomy is indicated. Retreatment with laser surgery or a surgical iridectomy may be needed.[1]

Laser iridoplasty

Laser iridoplasty can be considered in the presence of a patent LPI with a residual appositional angle.[1] 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.[44]

Lens extraction surgery

If residual angle closure is attributable to the lens, then lens extraction surgery with or without goniosynechialysis is considered. Early lens extraction may provide better long-term IOP control, and reduce the need for additional glaucoma agents, compared with LPI.[45][46]

Cholinergic agents may be used if there is residual angle closure after laser treatment.

Persistently elevated IOP in patients with acute or chronic ACG despite surgery

If IOP remains elevated after surgery, the initial management is with IOP-lowering drugs. First-line options include a topical prostaglandin analogue and/or a topical beta-blocker and/or a topical alpha-2 agonist.[1]

Topical prostaglandin analogues are potent IOP-lowering agents, and should be used first line.[47][48] They work by increasing uveoscleral outflow, and reach peak effectiveness 8 to 12 hours after administration.[39] Topical beta-blockers and alpha-2 agonists are typically used alone, or in combination at the discretion of the physician.

Chronic systemic carbonic anhydrase inhibitor therapy is associated with many adverse effects, and it should be reserved for patients with glaucoma refractory to other medical treatment.[39]

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.[49][50] [ ] [ ]

Repeat episode of acute ACG

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

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