Approach
Acute ACG presents with a change in vision or with often severe acute symptoms, such as pain in the affected eye, headache, and associated nausea or vomiting.[17] Chronic ACG is most often discovered incidentally during routine examination or during examination for another reason. ACG can also present with intermittent recurrent symptoms. Patients who are suspected of having ACG should be referred to ophthalmology care immediately.
History
Pain in the affected eye, blurred vision, halos around lights seen from one eye, headache, and associated nausea or vomiting suggest acute ACG.
Many patients with chronic ACG are asymptomatic. A history of ACG increases the risk of angle closure in the unaffected eye. There may be intermittent ache and/or blurred vision with haloes around lights seen from one eye, which resolve spontaneously. The patient may report a change in vision.
The patient’s family history should be reviewed in case it reveals a relative with ACG.[17][29]
The patient may be on medications that increase the risk of ACG, such as anticholinergic topical ocular medication (e.g., pupil dilators) or systemic medication (e.g., sulfonamides, topiramate, phenothiazines) because they induce angle narrowing.[27] It is important to be vigilant and aware of ophthalmic and systemic medications that can lead to ACG in predisposed patients.[30]
Examination
Visual acuity should be tested because it may be decreased.[29]
Examination of the eye may show it to be red with vascular congestion and corneal oedema. The pupil may be mid-dilated, asymmetric, or oval during or after an acute angle closure crisis. Pupil reactivity may be reduced during a crisis or completely absent following a crisis. Relative afferent pupillary defect may also be present.[17]
The intra-ocular pressure may be raised above 21 mmHg.[31]
Investigations
Slit-lamp examination may show central and peripheral anterior chamber depth narrowing, corneal oedema, lens changes, and corneal endothelial loss. Anterior chamber inflammation and iris abnormalities are suggestive of a recent or recurrent attack.[17]
Gonioscopy of both eyes should be performed in all patients in whom angle closure is suspected.[17] Gonioscopy refers to the technique used for viewing the anterior chamber angle of the eye for evaluation of angle structures. Special contact lenses (gonioscopy lenses) overcome the problem of total internal reflection of light rays from the chamber angle, and allow visualisation of the angle using obliquely inclined mirrors. The angle can be closed even in the absence of any other symptoms or signs.
If the clinician is uncertain about the gonioscopic findings, he/she can refer the patient for objective imaging of the angle via either ultrasound biomicroscopy or optical coherence tomography.[17]
Automatic testing of the visual field should be routinely done to assess the presence and extent of glaucomatous visual field loss.
Although not feasible in all patients, an attempt should be made to evaluate the fundus and optic nerve head using a direct ophthalmoscope or slit-lamp biomicroscope with an indirect lens, the central portion of a gonioscopy lens, or a non-mydriatic camera.[17]
Objective quantitative assessment of optic nerve damage can be obtained by imaging machines such as Heidelberg retinal tomography, optical coherence tomography, and GDx nerve fibre analysis.[32]
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It is usual for investigations and confirmation of the diagnosis to be completed before full treatment is initiated.
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