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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
Key points
- Sudden painless floaters, cobwebs, or diffuse visual loss + absent red reflex
- Commonest cause: proliferative diabetic retinopathy (~50%), then PVD with retinal tear
- MUST exclude retinal tear/detachment — B-scan ultrasound essential if fundal view obscured
- Many resolve spontaneously; vitrectomy if not clearing by 1–3 months or if retinal detachment
- Vision worst on waking (blood settles on macula), improves during day
Overview
Vitreous haemorrhage (VH) is bleeding into the vitreous cavity from retinal vessels. Commonest cause in adults is proliferative diabetic retinopathy (~50%). Second commonest is PVD causing a retinal tear and avulsing a vessel. Other causes include retinal vein occlusion, trauma, retinal macroaneurysm, and subarachnoid haemorrhage (Terson syndrome). The key concern is the underlying cause — a retinal tear or detachment may be hidden.
Epidemiology
Incidence ~7 per 100,000 per year. Proliferative DR accounts for ~50%, PVD with tear ~20%, vein occlusion ~10%.
Clinical Features
Symptoms
Sudden floaters — "cobwebs", "smoke", "dark spots"
Sudden painless visual loss
Red haze to vision
Preceding flashes — suggests retinal tear
Signs
Absent or diminished red reflex
Reduced VA
Fundal view obscured in dense haemorrhage
Investigations
First-line
B-scan ultrasonographyESSENTIAL when fundal view obscured — detects retinal detachment
Dilated fundoscopyIf possible — look for retinal tear, neovascularisation
Second-line
Blood glucose/HbA1cAssess diabetic status
BPHypertension contributes to vascular disease
Specialist
Fluorescein angiographyOnce blood clears — identifies underlying cause
Management
RCOphth Guidelines + NICE NG2421
Urgent assessment
- Same-day/next-day ophthalmology referral
- B-scan to exclude retinal detachment
- Urgent laser/cryotherapy if retinal tear found
2
Conservative (no detachment)
- Mild VH often clears over weeks to months
- Elevate head of bed
- Regular ultrasound follow-up
3
Surgical
- Vitrectomy if not clearing by 1–3 months, retinal detachment, or bilateral dense VH
- Diabetic VH: vitrectomy at 1 month if not clearing (NICE NG242)
- Treat underlying cause: PRP, laser, anti-VEGF
Complications
- Underlying retinal detachment: May be hidden behind blood
- Ghost cell glaucoma: Degenerated RBCs block trabecular meshwork
- Haemosiderosis: Chronic iron toxicity from persistent blood
UKMLA Exam Tips
- 1Sudden floaters + visual loss + absent red reflex = vitreous haemorrhage
- 2B-scan ultrasound is the MOST IMPORTANT investigation — must exclude retinal detachment
- 3Proliferative diabetic retinopathy is the commonest cause (~50%)
- 4Preceded by flashes → suspect PVD with retinal tear
- 5Vision worst on waking, improves during day — classic history
- 6Terson syndrome: vitreous haemorrhage + subarachnoid haemorrhage
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