Neuro-Ophthalmic
CN VI Palsy
Also known as: CN VI palsy, abducens palsy, sixth nerve palsy, lateral rectus palsy, horizontal diplopia abduction deficit
Filed as: Urgent
Source-cited from the record's own evidence list. Clinical content programme led by Dr Ankit Mathur, PhD, Grad Cert Ocu Thera, B.S. Optom. How the clinical content is governed
Clinical decision support only
Overview
Weakness of the lateral rectus, so the affected eye cannot turn fully outward. The result is side-by-side double vision, worst on gaze toward the weak muscle and when viewing in the distance, with the eye resting esotropic in primary gaze and the patient often turning the face to hold single vision. The pupil is unaffected, and because a sixth nerve palsy can be a false localising sign of raised intracranial pressure it warrants urgent assessment.
Recognition
Symptoms: what patients report
- New binocular horizontal diplopia.
- Symptoms are often worse at distance and in the direction of the affected lateral rectus.
- Patients may adopt a face turn to maintain single vision.
Signs: what the examination shows
- Esotropia in primary gaze.
- Failure or limitation of abduction in the affected eye.
- No fixed dilated pupil.
What OptoGuide™ covers for cn vi palsy
- Pattern reasoning: what this combination of findings points to, and its differentiators
- Don't-miss risks and escalation triggers
- Management tiers with linked Australian therapeutics
- Referral urgency, specialty, and letter drafting
Sources
- Abducens Nerve Palsy — EyeWiki
- The Neuro-Ophthalmology Survival Guide (Pane, Miller & Burdon) — standard reference text
- Isolated Abducens Nerve Palsy: Update on Evaluation and Diagnosis. Elder C, Hainline C, Galetta SL, Balcer LJ, Rucker JC. Current Neurology and Neuroscience Reports. 2016;16(8):69.
- The spectrum and differential diagnosis of acquired ocular motor nerve palsies: a clinical study of 502 patients. Hörner R, Kassubek J, Dreyhaupt J, Ludolph AC. Journal of Neurology. 2022;269(4):2140-2148.
- Etiologic distribution of isolated abducens nerve palsy: Analysis of 807 patients and literature review. Kim HJ, Kim HJ, Choi JY, et al. European Journal of Neurology. 2023;30(8):2471-2480.
Standard texts: Kanski's Clinical Ophthalmology: A Systematic Approach, Oxford Handbook of Ophthalmology, Oxford American Handbook of Ophthalmology, Signs in Ophthalmology: Causes & Differential Diagnosis.