Presenting Complaint:

• Mr Deng reports sudden, severe vision loss in his right eye that began earlier today without pain or warning.
• He states – “I was reading the newspaper this morning, and all of a sudden, I couldn’t see out of my right eye. It just went quite dark and I can barely see things from that side — no pain or anything though.”

Symptoms (SOCRATES):

• Site: Right eye – “It’s my right eye, everything’s just gone dark and blurry.”
• Onset: Started 3.5 hours ago, was sudden, within seconds– “It happened in a flash at around 7am this morning so 3.5 hours ago. One second I was reading, the next, very little.”
• Character: Significant visual loss – “It’s like a curtain dropped. I can still just about see light and some blurred shapes but not more than that.”
• Radiation: None – “It’s only the eye, nowhere else.”
• Associated symptoms: None – “No pain, no headache, no flashes or floaters.”
• Time: Constant since onset – “It’s been like this since around 7am this morning.”
• Exacerbating/Alleviating factors: None – “Nothing makes it better or worse, it’s just stayed the same.”
• Severity: Significant visual loss, although with intact light perception – “From my right eye everything is dark and blurry, however I can still see some vague shapes and some light.”

Other relevant negative findings:

• No headache or jaw claudication – “No headaches, no issues chewing.”
• No flashing lights or floaters – “Didn’t see anything like that before it happened.”
• No weakness, speech changes, or balance issues – “No other problems, I feel normal otherwise.”
• No trauma or recent eye surgery – “My eyes have been fine till now.”
• No changes to the left eye – “My left eye is completely fine.”

Systemic Symptoms:

• Fatigue: No 
• Fever: No 
• Night Sweats: 
• Unintended Weight Loss: No 
• Chest or Shoulder Tip Pain: No 
• Shortness of Breath or Cough: No 
• Peripheral Oedema: No 
• Rashes or Skin Changes: No 
• Headache: No
• Change in Bowel Habits: No 
• Urinary symptoms: No

Past Medical History:

• Atrial fibrillation – Diagnosed 5 years ago, on warfarin
• Hypertension – Diagnosed 10 years ago, controlled on ramipril
• Cataract surgery – Right eye, uneventful, 3 years ago
• No prior strokes, TIAs, or ischaemic heart disease

 Drug History:

• Warfarin 3mg once daily 
• Ramipril 5mg once daily
• Occasionally paracetamol for joint aches

 Allergies:

• Penicillin – causes widespread rash and itching 

 Family History:

• Mother – Died of stroke aged 76
• Father – Type 2 diabetes, now deceased
• Brother – Alive, has high blood pressure
• No known family history of eye disease or clotting disorders

 Social History:

• Lifestyle: Retired civil engineer, lives with wife
• Activities and Hobbies: Chess, cooking traditional Sichuan dishes, online language courses
• Smoking: Never smoked
• Alcohol: Drinks 1–2 small glasses of red wine per week (~3 units) – “Only with family dinners.”
• Recreational Drugs: Never used 
• Exercise: Walks 3–4 times a week, light tai chi – “I like to keep moving.”

 Ideas, Concerns, and Expectations:

• Ideas: “I wonder if it’s a stroke in the eye? It felt just like that, no warning.”
• Concerns: “I’m frightened this might be permanent. I rely on my eyes to stay independent.”
• Expectations: “I want to know exactly what’s happened, if it can be treated, and if I need to stay in hospital.”

Observations:

– Respirations (Breaths/min): 16

– Oxygen Saturation (%): 98%

– Air or Oxygen: Air

– Blood Pressure (mmHg): 148/82

– Pulse (Beats/min): 96, irregularly irregular

– Consciousness (AVPU): A

– Temperature (Celsius): 36.8

NEWS Total Score: 1

Eye Examination:

Inspection:

• No ptosis, swelling, redness or discharge
• Pupil appears mid-dilated and non-reactive to light
• No conjunctival injection or chemosis
• No periorbital bruising or trauma

Visual Acuity (Snellen chart – each eye separately):

• Right Eye (OD): Hand movements only
• Left Eye (OS): 6/9 with correction

Pupillary Reflexes:

• Right pupil: fixed, dilated, non-reactive to light
• Left pupil: briskly reactive
• Relative Afferent Pupillary Defect (RAPD): Present on right (positive swinging flashlight test)

Swinging light test should be demonstrated or verbalised.

Visual Fields (by confrontation):

• Unable to assess in right eye due to significantly reduced vision
• Gross confrontation in fields appear normal in left eye

Eye movements:

• Full range of eye movements, no diplopia or restrictions

Fundoscopy

Right Eye:

Candidate should verbalise findings on fundoscopy image:

Key Findings
 Pale retina with a cherry-red spot at the macula 

Image sourced from Moran Core – Clinical Ophthalmology Source for Education. Available at https://morancore.utah.edu/basic-ophthalmology-review/central-retinal-artery-occlusion/ (Image B) 

Left Eye:

• Normal optic disc
• Normal macula
• Retinal vessels normal calibre and perfusion
• No haemorrhages or exudates

Choose EITHER examiner viva questions OR patient communication questions

Patient questions:

1. “Why did I suddenly lose vision in one eye? Will my sight come back?”
2. “Is this going to affect both my eyes or just the one?”
3. “What caused this blockage? Could it happen because of something I did or my health?”

Exemplar answers:

1) “I understand how frightening this sudden vision loss must be for you. What has happened is a blockage in the artery that supplies blood to the retina, which is the part of your eye responsible for vision. Because the retina has been deprived of blood, some damage has occurred. Unfortunately, although recovery can vary, this damage is often permanent, so recovery of vision is unlikely. However, our main goal now is to prevent any further problems and protect the other eye. We will work together on that.”

2) “At the moment, it’s only affecting this eye, which is a relief. But it’s important we act quickly to find out why this happened, so we can reduce the risk of it happening to your other eye or other parts of your body like your brain. We’ll investigate and manage any underlying conditions to keep you as safe as possible.”

3) “This type of blockage is usually caused by a clot or material that travels through your bloodstream and gets stuck in the small artery to your eye. Often, this is linked to medical issues like high blood pressure, irregular heartbeat—such as atrial fibrillation—or high cholesterol. These are common conditions that we can manage with medication and lifestyle changes to help prevent this from happening again. It’s not something you did intentionally, but working with you to control these risks is very important.”

Examiner questions:

1) What is the differential diagnosis and which is the most likely?

• Central retinal artery occlusion (most likely)
• Central retinal vein occlusion
• Retinal detachment
• Optic neuritis

2) What are the main risk factors for central retinal artery occlusion?

• Age >50 years
• Hypertension
• Diabetes
• Hyperlipidaemia
• Smoking
• Atrial Fibrillation
• Atherosclerosis
• Previous stroke or TIA
• Vasculitis e.g. Giant Cell Arteritis

3) What clinical signs and symptoms would you expect in a patient with CRAO?

• Sudden, painless, profound vision loss in one eye
• Relative afferent pupillary defect (RAPD)
• Pale retina with a cherry red spot on fundoscopy
• Possibly a history of amaurosis fugax; no ocular pain

4) What investigations would you arrange to confirm the diagnosis and assess the patient?

• Urgent fundoscopy to identify the pale retina and cherry red spot
• Optical coherence tomography (OCT) if available
• Carotid Doppler ultrasound to assess for carotid artery stenosis
• Echocardiogram to screen for any cardioembolic source from AF/valvular disease
• ECG and Holter monitoring to identify atrial fibrillation or other arrhythmias 
• Blood tests: full blood count, inflammatory markers (ESR, CRP) to exclude giant cell arteritis, lipid profile, glucose + HbA1c, coagulation and vasculitis screen, especially in young patients
• Brain imaging (CT/MRI) to rule out concurrent stroke if neurological symptoms are present 

5) What immediate management steps would you take in a patient presenting with CRAO?

• Urgent referral to ophthalmology and stroke team (as there is an increased risk of a subsequent CVA in the next few days/weeks/months) 
• Attempt to lower intraocular pressure (e.g., ocular massage, acetazolamide, topical beta-blockers) although evidence is limited
• High-flow oxygen administration may be considered
• Immediate assessment and management of underlying vascular risk factors
• If giant cell arteritis suspected (e.g. in patient >50), start high-dose corticosteroids immediately

It should be noted that there is limited evidence for the above medical therapies – although prognosis can vary, once vision is lost, it is often irreversible. 

• Tissue plasminogen activator (tPA) is a controversial invasive management option but has a high risk of adverse effects such as  intracranial hemorrhage, choroidal hemorrhage, or death

6) How would you manage this patient long-term to prevent further vascular events?

• Control vascular risk factors: strict blood pressure, diabetes, and lipid management
• Antiplatelet therapy (e.g. aspirin)
• Anticoagulation if atrial fibrillation is present
• Lifestyle modifications: smoking cessation, healthy diet, exercise
• Regular follow-up with ophthalmology and cardiology/stroke services
• Patient education on recognising stroke symptoms