Eye Movements in Coma
OVERVIEW
A simplified approach to spontaneous eye movements in coma is:
- roving eye movements — metabolic/ toxic encephalopathy most likely, or although they can also occur with bilateral lesions above the brainstem.
- other ‘weird and wonderful’ eye movements — structural, metabolic or toxicological cause of comas.
- saccadic eye movements or fixing and following — pseudocoma (feigned coma).
Most individuals have a degree of exophoria when drowsy for any reason and any underlying strabismus tends to worsen — thus dysconjugate gaze is difficult to interpret in the stuporous or comatose patient.
TYPES OF EYE MOVEMENTS
Eye movements seen in the comatose patient include:
- roving eye movements —
Description: slow random predominantly horizontal conjugate eye movements (though there may be a degree of exophoria) similar to those seen in deep sleep.
Likely cause: metabolic encephalopathy (may be absent in deep coma), bilateral supranuclear lesions - ocular bobbing —
Description: Rapid, conjugate, downward movement; slow return to primary position
Likely cause: Pontine strokes; other structural, metabolic, or toxic disorders - ocular dipping —
Description: Slow downward movement; rapid return to primary position
Likely cause: Unreliable for localization; follows hypoxic-ischemic insult or metabolic disorder - reverse ocular bobbing —
Description: Rapid upward movement; slow return to primary position
Likely cause: Unreliable for localization; may occur with metabolic disorders - reverse ocular dipping —
Description: Slow upward movement; rapid return to primary position
Likely cause: Unreliable for localization; pontine infarction and with AIDS - ping-pong gaze —
Description: Horizontal conjugate deviation of the eyes, alternating every few seconds
Likely cause: metabolic encephalopathy, bilateral cerebral hemispheric dysfunction; toxic ingestion - periodic alternating gaze deviation —
Description: Horizontal conjugate deviation of the eyes, alternating every 2 minutes
Likely cause: Hepatic encephalopathy; disorders causing periodic alternating nystagmus and unconsciousness or vegetative state - vertical myoclonus —
Description: vertical pendular oscillations (2–3 Hz)
Likely cause: Pontine strokes - horizontal myoclonus —
Description: rapid horizontal pendular oscillations; the eyes appear to be shaking.
Likely cause: Serotonin toxicity - monocular eye movements —
Description: Small, intermittent, rapid monocular horizontal, vertical, or torsional movements
Likely cause: Pontine or midbrain destructive lesions, perhaps with coexistent seizures
References and Links
CCC Neurocritical Care Series
Emergencies: Brain Herniation, Eclampsia, Elevated ICP, Status Epilepticus, Status Epilepticus in Paeds
DDx: Acute Non-Traumatic Weakness, Bulbar Dysfunction, Coma, Coma-like Syndromes, Delayed Awakening, Hearing Loss in ICU, ICU acquired Weakness, Post-Op Confusion, Pseudocoma, Pupillary Abnormalities
Neurology: Anti-NMDA Encephalitis, Basilar Artery Occlusion, Central Diabetes Insipidus, Cerebral Oedema, Cerebral Venous Sinus Thrombosis, Cervical (Carotid / Vertebral) Artery Dissections, Delirium, GBS vs CIP, GBS vs MG vs MND, Guillain-Barre Syndrome, Horner’s Syndrome, Hypoxic Brain Injury, Intracerebral Haemorrhage (ICH), Myasthenia Gravis, Non-convulsive Status Epilepticus, Post-Hypoxic Myoclonus, PRES, Stroke Thrombolysis, Transverse Myelitis, Watershed Infarcts, Wernicke’s Encephalopathy
Neurosurgery: Cerebral Salt Wasting, Decompressive Craniectomy, Decompressive Craniectomy for Malignant MCA Syndrome, Intracerebral Haemorrhage (ICH)
— SCI: Anatomy and Syndromes, Acute Traumatic Spinal Cord Injury, C-Spine Assessment, C-Spine Fractures, Spinal Cord Infarction, Syndomes,
— SAH: Acute management, Coiling vs Clipping, Complications, Grading Systems, Literature Summaries, ICU Management, Monitoring, Overview, Prognostication, Vasospasm
— TBI: Assessment, Base of skull fracture, Brain Impact Apnoea, Cerebral Perfusion Pressure (CPP), DI in TBI, Elevated ICP, Limitations of CT, Lund Concept, Management, Moderate Head Injury, Monitoring, Overview, Paediatric TBI, Polyuria incl. CSW, Prognosis, Seizures, Temperature
ID in NeuroCrit. Care: Aseptic Meningitis, Bacterial Meningitis, Botulism, Cryptococcosis, Encephalitis, HSV Encephalitis, Meningococcaemia, Spinal Epidural Abscess
Equipment/Investigations: BIS Monitoring, Codman ICP Monitor, Continuous EEG, CSF Analysis, CT Head, CT Head Interpretation, EEG, Extradural ICP Monitors, External Ventricular Drain (EVD), Evoked Potentials, Jugular Bulb Oxygen Saturation, MRI Head, MRI and the Critically Ill, Train of Four (TOF), Transcranial Doppler
Pharmacology: Desmopressin, Hypertonic Saline, Levetiracetam (Keppra), Mannitol, Midazolam, Sedation in ICU, Thiopentone
MISC: Brainstem Rules of 4, Cognitive Impairment in Critically Ill, Eye Movements in Coma, Examination of the Unconscious Patient, Glasgow Coma Scale (GCS), Hiccoughs, Myopathy vs Neuropathy, Neurology Literature Summaries, NSx Literature Summaries, Occulocephalic and occulovestibular reflexes, Prognosis after Cardiac Arrest, SIADH vs Cerebral Salt Wasting, Sleep in ICU
- Posner JB, Saper CB, Schiff N, Plum F. Plum and Posner’s Diagnosis of Stupor and Coma 4e Oxford university Press, 2009.
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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