I can see clearly now

aka Ophthalmology Befuddler 024

A 68 year-old man has presented to the emergency department.

You ask, “What’s wrong?”.

He says, “Nothing”.

You ask, “Why are you here?”.

He points at his wife and says, “She made me come.”

You ask, “Why did your wife make you come to the emergency department?”.

He says, “Well, for a couple of minutes there I couldn’t see out of my right eye, it’s better now though.”

You look at the chart and note the past history of hypertension, coronary artery disease, diet-controlled type 2 diabetes mellitus and the fact that he is a reformed smoker. He has never had migraines or giant cell arteritis and his eyes were open at the time of the transient monocular visual loss…


Q1. What is the likely diagnosis, and what are the differentials?
Answer and interpretation

Amaurosis fugax — a transient ischemic attack affecting the retina.

Common causes of non-traumatic transient visual loss include:

  • amaurosis fugax (usually minutes) — usually embolic or thrombotic; can occur secondary to hypoperfusion states, hyperviscosity or vasospasm.
  • migraine (can be without headache)
  • one eye closed!

Uncommon causes include:

  • papilloedema (may be associated with visual loss lasting seconds)
  • other causes of ischemic optic neuropathy, e.g. giant cell arteritis
  • impending central retinal vein occlusion
  • glaucoma
  • posterior reversible encephalopathy syndrome (PRES)
  • large vessel occlusion or dissection, e.g. ocular ischemic syndrome (carotid occlusive disease), vertebrobasilar insufficiency, and carotid or vertebral artery dissection
  • functional visual loss, e.g. hysteria, malingering

Q2. What features should be assessed on history and examination?
Answer and interpretation


  • Classically there is transient monocular vision loss lasting seconds to minutes, but sometimes up to hours, with a return to normal vision. This may be experienced as a curtain coming down, blurring or fogging.
  • There may have been previous episodes.
  • Assess for cardiovascular/ stroke risk factors.


  • Visual acuity and visual fields — normal following resolution of the attack; sectorial or complete monocular visual field loss during the attack.
  • Full ophthalmic exam is generally normal — an embolus is rarely seen in a retinal artery.
  • Cardiovascular and neurological exam — assess for cardiovacular disease and evidence of cerebral ischemia.

Q3. What investigations are required?
Answer and interpretation

Essentially a TIA work up, which may include:

  • Bedside — BSL, ECG
  • Laboratory — FBC, UEC, lipid profile, fasting glucose, HbA1c
  • Imaging — Echocardiogram, carotid doppler ultrasound, CT/MRI brain

Q4. What is the management of this condition?
Answer and interpretation
  • Refer to neurology +/- cardiology/ vascular surgery depending on the work up.
  • Start aspirin.
  • Recurrent amaurosis fugax may require early investigation and intervention.
  • Treat underlying causes and risk factors.

Q5. What is ocular ischemic syndrome?
Answer and interpretation

A condition caused by carotid artery occlusion (>90%), or rarely ophthalmic artery disease, that may underlie amaurosis fugax.

  • It typically presents with ocular or periorbital pain and afterimages or prolonged recovery of vision after exposure to bright light. Symptoms may mimic central retinal artery occulsion (CRAO).
  • The signs mimic central retinal vein occulsion (CRVO) with widespread hemorrhages and neovascularisation.
  • Treatment usually includes carotid endarterectomy and photocoagulation.



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.

| INTENSIVE | RAGE | Resuscitology | SMACC

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.