Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 7 Sept 2026Clinical review pending
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A field defect may have an urgent cause
Sudden visual-field loss, associated neurological symptoms or a painful red eye should not be attributed automatically to chronic glaucoma because an optic cup or abnormal scan is also present.
Action: Use the appropriate same-day ocular or emergency neurological pathway for new acute symptoms, and arrange prompt specialist assessment for atypical progressive optic neuropathy.
Synopsis
Interpret optic nerve appearance, retinal nerve-fibre imaging and perimetry together, recognising test artefacts, anatomical variation and patterns that require a different diagnostic pathway.
Assess the neuroretinal rim and disc size, not a cup-to-disc ratio in isolation; large normal discs can have large cups.
A glaucomatous field pattern should make anatomical sense alongside the disc and retinal nerve-fibre findings.
Read the test quality and raw results before accepting an OCT colour code or a visual-field summary index.
Key red flags
New visual-field loss with weakness, speech disturbance or another acute focal neurological symptom requires emergency stroke assessment: call 999, including when recent symptoms have resolved.
Investigation priorities
01
Stereoscopic optic nerve examination with baseline imagingFirst step
Describe disc size, rim configuration, haemorrhage and the surrounding nerve-fibre layer.
Management branches
Structural assessmentDescribe what the optic nerve shows
An optic disc appears cupped, asymmetric or otherwise suspicious during examination.
Establish the quality of the view and record disc size, focal rim shape, pallor, haemorrhage and relevant nerve-fibre findings in each eye.
Obtain baseline photography or OCT when available and compare with previous images, checking that apparent differences are not simply changes in image scale or quality.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 7 Sept 2026; clinical approval remains outstanding.