A 61-year-old man notices a sudden, painless wedge-shaped blind area in the upper part of vision in his right eye while reading the newspaper. It appeared within seconds and has not changed since. He has type 2 diabetes and high cholesterol. There is no eye pain, no headache and no jaw pain. He can still read small print with the affected eye.
Examination Findings
Right eye: visual acuity 6/9, left 6/6. A subtle right relative afferent pupillary defect. Fundus of the right eye shows a sharply demarcated area of pale, oedematous retina in the inferior distribution with a visible refractile embolus lodged at a bifurcation — a Hollenhorst plaque. The rest of the retina and the left eye show only mild diabetic background changes without macular oedema. Visual field testing later confirms a superior sectoral defect matching the inferior retinal whitening.
Investigations
Carotid Doppler ultrasound and cardiac evaluation are arranged the same week to seek the embolic source, as with any retinal arterial occlusion. Blood pressure, HbA1c and fasting lipids are checked and optimised. Fluorescein angiography, if performed, shows delayed filling confined to the affected branch. Inflammatory markers are checked to exclude giant cell arteritis given his age.
Questions to Think About
- Why does an inferior retinal lesion cause a superior field defect?
- What does the visible Hollenhorst plaque tell you about the source?
- Why is the management mostly about the carotids and heart rather than the eye?
Diagnosis
Branch retinal artery occlusion, right eye (inferior division).
Reasoning
Reasoning: A sudden painless sectoral field defect with a sharply demarcated area of retinal whitening and a visible embolus is a branch retinal artery occlusion. The inferior retina maps to the superior field, which is why he loses the upper wedge of vision. The refractile Hollenhorst plaque points to cholesterol emboli, most often from carotid atheroma. Because the fovea is outside the affected sector, central acuity is preserved — which is why he can still read. Diagnosis: branch retinal artery occlusion, right eye, inferior division. Management: typical management is urgent vascular workup — carotid imaging, cardiac rhythm assessment, and aggressive control of blood pressure, lipids and diabetes — because the same embolic process threatens the brain and the fellow eye. There is no proven acute ocular treatment that restores the infarcted sector; follow-up watches for the rare complication of neovascularisation at the ischaemic border.
Differential Diagnosis
- Central retinal artery occlusion — ruled out: the whitening is sectoral, not whole-retina, and central acuity is preserved.
- Branch retinal vein occlusion — ruled out: veins are not dilated or tortuous and there are no flame haemorrhages; the picture is pale ischaemia, not venous congestion.
- Retinal migraine — ruled out: the defect is fixed and persistent, not transient, and the embolus is visible.
- Amaurosis fugax — ruled out: that is transient; this deficit has persisted.
Management
Typical management includes prompt carotid Doppler and cardiac evaluation for the embolic source, with optimisation of blood pressure, glycaemic control and lipids per local protocols. The patient is referred through the stroke-prevention pathway. Ophthalmology follow-up monitors for neovascular complications at the ischaemic border. He is counselled that the wedge of field loss is permanent, that the fellow eye needs surveillance, and that transient neurological symptoms require emergency care.
Key Learning Points
- BRAO gives a sectoral, sharply demarcated area of retinal whitening with a matching sectoral field defect — inferior retina, superior field.
- A visible embolus at a bifurcation is diagnostic and points to the likely source (carotid atheroma for cholesterol emboli).
- Preserved central acuity does not mean a benign event — it is a stroke warning.
- Management is systemic: find and treat the embolic source; no acute eye intervention has proven benefit.
Red Flags
- Visible Hollenhorst plaque — cholesterol embolus; the carotids must be imaged.
- Any transient weakness, speech change or further visual loss — emergency stroke pathway.
- Giant cell arteritis symptoms in an older patient with arterial occlusion — check inflammatory markers.
Educational content only — not medical advice. Clinical decisions must be made by a qualified professional for the individual patient.