Pupil Abnormalities & RAPD

Key points

• RAPD (Marcus Gunn pupil): swinging-torch test — pupil dilates when light moved to affected eye; indicates optic nerve/severe retinal disease (e.g. optic neuritis).
• Argyll Robertson pupil: small irregular pupils — accommodate but do not react to light; neurosyphilis (also dorsal midbrain lesions).
• Horner's syndrome: ptosis · miosis · anhidrosis (± enophthalmos) — check for Pancoast tumour, carotid dissection (painful).
• Holmes-Adie pupil: dilated pupil with light-near dissociation + absent ankle jerks — benign, young women.