General MedicineTier 1Approach to a presentation

Undifferentiated presentations - visual disturbance

Red flags

Sudden painless vision loss - retinal artery/vein occlusion, retinal detachment, vitreous haemorrhage, ischaemic optic neuropathy - all emergencies
Amaurosis fugax - transient monocular vision loss = TIA equivalent, urgent stroke workup
Vision loss + headache + jaw claudication/scalp tenderness (>50y) - giant cell arteritis - urgent steroids, do not wait for biopsy
Flashes/floaters + curtain/shadow - retinal detachment
Diplopia + pupil involvement (third nerve palsy with a dilated pupil) - posterior communicating artery aneurysm until excluded

Sudden painless monocular vision loss

Central/branch retinal artery occlusion (embolic, GCA), central/branch retinal vein occlusion, retinal detachment, vitreous haemorrhage, anterior ischaemic optic neuropathy (arteritic - GCA; non-arteritic)

Transient vision loss

Amaurosis fugax (carotid/embolic), migraine aura (scintillating scotoma, progresses over minutes, resolves), papilloedema (transient obscurations with position change)

Gradual vision loss

Cataract, refractive error, macular degeneration, chronic glaucoma, diabetic retinopathy

Diplopia

Cranial nerve III/IV/VI palsy (vascular vs compressive - pupil involvement suggests compressive, e.g., aneurysm), myasthenia gravis, thyroid eye disease, internuclear ophthalmoplegia (MS)

Visual field defects

Chiasmal (bitemporal hemianopia - pituitary), retrochiasmal (homonymous hemianopia - stroke)

Onset (sudden vs gradual), monocular vs binocular, pain, associated headache/scalp tenderness/jaw claudication
Flashes, floaters, curtain/shadow effect
Vascular risk factors, atrial fibrillation, diabetes
Systemic symptoms suggesting GCA (age >50, temporal headache, jaw claudication, PMR symptoms)

Visual acuity, visual fields (confrontation), pupillary responses (RAPD), extraocular movements
Fundoscopy - disc swelling/pallor, retinal whitening/cherry-red spot (CRAO), venous engorgement/haemorrhages (CRVO), retinal detachment appearance
Temporal artery tenderness/thickened, reduced pulsation if GCA suspected

ESR/CRP urgently if GCA suspected - start steroids on clinical suspicion, do not wait for temporal artery biopsy
Carotid Doppler, ECG/echo (AF, embolic source) for amaurosis fugax/CRAO
MRI brain/orbits for compressive lesions, optic neuritis, stroke
Same-day ophthalmology for suspected retinal detachment, CRAO, vitreous haemorrhage

CRAO: time-critical (ophthalmology emergency though evidence for reperfusion interventions is limited) - treat as stroke equivalent, urgent vascular workup
GCA: high-dose corticosteroids started immediately on clinical suspicion, before biopsy, to prevent contralateral eye involvement/permanent blindness
Retinal detachment/vitreous haemorrhage: urgent ophthalmology referral for surgical assessment
Amaurosis fugax: manage as TIA - urgent stroke clinic, carotid imaging, antiplatelet/statin, AF workup
Third nerve palsy with pupil involvement: urgent CT/MR angiography to exclude posterior communicating artery aneurysm
Migraine with typical aura - reassurance if classic pattern, red flags excluded

Waiting for temporal artery biopsy before starting steroids in suspected GCA risks irreversible bilateral blindness
A pupil-sparing third nerve palsy is more likely microvascular (diabetes, hypertension); a pupil-involving one is more likely compressive (aneurysm) - the distinction changes urgency dramatically
Amaurosis fugax is frequently under-triaged as "just a funny turn" rather than recognised as a stroke-equivalent emergency
Migraine aura that is atypical (non-scintillating, prolonged, first episode >50 years) should not be assumed benign without exclusion of other causes

"Any suspicion of GCA gets steroids today - the biopsy can wait, the vision can't."
"A dilated pupil with a third nerve palsy goes straight to imaging for an aneurysm."

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