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
!
Acute ptosis can signal vascular disease
New ptosis with diplopia, an abnormal pupil, severe headache, neck pain or neurological signs may indicate an aneurysm, arterial dissection or another acute neurological lesion.
Action: Arrange immediate emergency assessment when these features suggest an acute neurovascular cause; do not delay appropriate imaging for pharmacological pupil testing.
Synopsis
Localise a drooping eyelid and unequal pupils, recognise acute neurovascular presentations and distinguish urgent investigation from established benign or mechanical causes.
Measure and compare pupils in bright and dim conditions before instilling diagnostic drops.
Anisocoria greater in light points towards impaired constriction of the larger pupil.
Anisocoria greater in darkness points towards impaired dilation of the smaller pupil.
Key red flags
Sudden ptosis with new diplopia or restricted eye movements, even if the pupils appear equal.
Investigation priorities
01
Pupils in light and darknessFirst step
Identify which pupil behaves abnormally under different illumination conditions.
Management branches
Acute neurological concernTransfer for immediate assessment
New ptosis or anisocoria accompanies concerning pain, diplopia or neurological signs.
Document onset, pupils, motility and associated symptoms without creating avoidable delay.
Arrange emergency assessment and explicitly communicate suspected aneurysm, dissection or acute neurological disease.
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.