Angle-closure glaucoma

Acute angle-closure glaucoma (ACG) is an urgent but uncommon dramatic symptomatic event which can present with blurring of vision, painful red eye, headache, nausea, and vomiting. Patients who are suspected of having acute ACG should be referred to ophthalmology care immediately.

Chronic ACG is diagnosed by peripheral anterior synechiae on gonioscopy, progressive optic nerve damage, and visual field loss.[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp

History

Clinicians should identify key risk factors for ACG, including:

• Female sex

• Hyperopia

• Shallow peripheral anterior chamber

• Angle closure in the fellow eye

• Asian or Inuit ethnicity

• Advanced age (>50 years)

• Family history of glaucoma

• Lens opacity

• Use of drugs that induce pupillary block and displacement of the lens-iris diaphragm (e.g., sulfonamides, acetazolamide, cyclopentolate, atropine, topiramate).

Chronic ACG may be detected incidentally at routine eye examination. These patients may be mostly asymptomatic with:

• intermittent and/or recurrent angle closure symptoms (e.g., intermittent ache and/or blurred vision with halos around lights [which resolve spontaneously])

• risk factors for ACG.

Examination and initial assessment

Anatomical features of both eyes are invariably similar; an untreated fellow eye is at high risk of ACG.[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp ​ Consider an alternative diagnosis if the fellow eye has a wide open angle.

Characteristic clinical signs and symptoms of acute ACG include:[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp

• Ocular history, specifically vision changes (may be decreased)

• Hyperopia (anterior chamber depth and volume are smaller)

• Corneal oedema (experienced as blurred vision and occasionally as halos around lights)

• Mid-dilated pupil

• Lens opacities (e.g., cataracts, glaucomflecken [the appearance of grayish-white spots on anterior lens subsequent to an attack of acute angle closure])

• Vascular congestion (i.e., conjunctival and episcleral); eye may appear red

• Eye pain

• Headache

• Nausea and vomiting

Intra-ocular pressure (IOP), measured by Goldmann applanation tonometry, may be raised above 21 mmHg.[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp [29]Gazzard G, Foster PJ, Devereux JG, et al. Intraocular pressure and visual field loss in primary angle closure and primary open angle glaucomas. Br J Ophthalmol. 2003 Jun;87(6):720-5. http://www.ncbi.nlm.nih.gov/pubmed/12770969?tool=bestpractice.com ​ In acute ACG, IOP may be above 40 mmHg.

The initial assessment should include the following tests.

• Slit-lamp examination: may reveal shallow central and peripheral anterior chamber depth, corneal oedema, lens changes, and corneal endothelial loss.[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp ​ Optic disc examination, employing slit lamp or funduscopy (direct ophthalmoscope), may show typical changes of glaucoma, such as a large optic cup and nerve fibre loss. Anterior chamber inflammation and iris abnormalities are suggestive of a recent or recurrent attack.

• Gonioscopy: definitive test for diagnosing primary angle-closure disease. Usually performed at the slit lamp. Both eyes should be investigated; each eye should be numbed prior to evaluation. Gonioscopy affords a view of the anterior chamber angle of the eye to evaluate angle structures, and may be therapeutic. Gonioscopy should be performed in a relatively dark room, and prior to instilling dilating drugs to rule out eyes susceptible to angle closure.

• Static perimetry: identifies the presence and degree of glaucomatous visual field loss during initial diagnosis and subsequently during follow-up care.[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp

Other investigations

Several additional investigations may be considered.

• Ultrasound biomicroscopy: can provide objective documentation of angle closure when gonioscopic findings are unclear (e.g., preclusion by corneal disease or poor patient cooperation). Useful for demonstrating specific aetiologies of angle closure, such as plateau iris or supraciliary body fluid, and for demonstrating dynamic changes in the angle during light and dark, and after other provocative tests that trigger closure, and after treatment. It may provide better characterisation of the posterior iris and ciliary body than Anterior segment optical coherence tomography (AS-OCT), but it is operator dependent and more time consuming.[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp

• AS-OCT: can provide objective documentation of angle closure when gonioscopic findings are unclear (e.g., preclusion by corneal disease or poor patient cooperation). Quantitative characteristics include angle opening depth, trabecular-iris space area, angle recess area, iridotrabecular contact index, lens vault, and iris volume. AS-OCT is useful for demonstrating dynamic changes in the angle during light and dark. AS-OCT is less capable of defining specific aetiologies for angle closure because it cannot effectively image structures behind the iris (e.g., the ciliary body).[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp

• Objective quantitative assessment of optic nerve damage: obtained using Heidelberg retinal tomography, retinal optical coherence tomography, and GDx nerve fibre analysis.[1]American Academy of Ophthalmology. Preferred practice pattern: primary angle closure. Nov 2020 [internet publication]. https://www.aao.org/preferred-practice-pattern/primary-angle-closure-disease-ppp [30]Michelessi M, Lucenteforte E, Oddone F, et al. Optic nerve head and fibre layer imaging for diagnosing glaucoma. Cochrane Database Syst Rev. 2015 Nov 30;(11):CD008803. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD008803.pub2/abstract http://www.ncbi.nlm.nih.gov/pubmed/26618332?tool=bestpractice.com [ ] What is the accuracy of scanning laser polarimetry (GDx) for diagnosing glaucoma?/cca.html?targetUrl=https://www.cochranelibrary.com/cca/doi/10.1002/cca.2822/fullShow me the answer [ ] What is the accuracy of confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph [HRT]) for diagnosing glaucoma?/cca.html?targetUrl=https://www.cochranelibrary.com/cca/doi/10.1002/cca.2821/fullShow me the answer [ ] What is the accuracy of macular parameters measured using optical coherence tomography (OCT) for diagnosing glaucoma?/cca.html?targetUrl=https://www.cochranelibrary.com/cca/doi/10.1002/cca.3299/fullShow me the answer