“Blood clot in the eye” is a catch‑all phrase people use for several different problems. It might be a harmless surface bleed that causes a bright red patch on the white of the eye (a subconjunctival haemorrhage), a pool of blood in front of the iris (hyphaema), bleeding into the jelly of the eye (vitreous haemorrhage), or an actual blockage of a retinal artery or vein — sometimes called an eye stroke. Some look dramatic but are usually benign; others cause sudden vision changes and need urgent care.
This guide explains the types of “blood clots” in the eye, what causes them, who’s at risk, and the symptoms that help tell them apart. You’ll learn when to seek urgent help in Australia, how specialists diagnose these conditions, treatment options, recovery times, ways to reduce your risk, and how to access expert care in Sydney.
What do people mean by "blood clot in the eye"?
People use “blood clot in the eye” for any eye bleed. Medically it may refer to: a subconjunctival haemorrhage (burst capillary on the white, dramatic but harmless), a hyphaema (blood pooling in front of the iris), a vitreous haemorrhage (blood in the eye’s gel), or a true retinal vein/artery blockage (“eye stroke”) that can threaten sight.
Is a blood clot in the eye dangerous?
It depends on the type. A subconjunctival haemorrhage looks dramatic but is usually harmless, painless, and clears within one to two weeks without affecting vision. By contrast, hyphaema, vitreous haemorrhage, and especially retinal vessel blockages can threaten sight. Sudden vision loss in one eye suggests a retinal artery occlusion (an eye stroke) and is an emergency. If there’s pain, vision change, trauma, or recurrent bleeds, get urgent assessment.
Causes and risk factors
Causes differ by type. Surface bleeds usually follow a brief pressure spike or minor trauma, while true “blood clots” on the retina reflect circulation problems. Diabetes and high blood pressure appear repeatedly across several conditions, with age and medicines also playing a role.
- Subconjunctival haemorrhage: Straining (cough, sneeze, vomiting), minor trauma/eye rubbing, contact lenses, blood thinners, hypertension, diabetes, age.
- Hyphaema: Usually blunt eye trauma; occasionally after eye surgery.
- Vitreous haemorrhage: Diabetic eye disease; trauma.
- Retinal vein/artery occlusion: High blood pressure, high cholesterol/atherosclerosis, diabetes, older age; smoking.
Symptoms by type: how to tell them apart
Different problems feel very different. If you’re worried you’ve got a “blood clot in the eye”, these patterns help you tell a harmless surface bleed from sight‑threatening issues. Always prioritise any change in vision, pain, or symptoms after trauma for urgent assessment.
- Subconjunctival haemorrhage: Bright‑red patch; no pain; vision normal.
- Hyphaema: Visible blood before the iris; often trauma; pain/blur.
- Vitreous haemorrhage: Sudden new floaters or haze; blurred vision.
- Retinal vein occlusion (RVO): Painless blurring or loss in one eye.
- Retinal artery occlusion (eye stroke): Sudden, painless severe vision loss; one eye; emergency.
When to seek urgent care in Australia
If you suspect a “blood clot in the eye”, timing matters. In Australia, any sudden change in vision should be treated as urgent. When severe, call 000 or go straight to the nearest emergency department; otherwise arrange a same‑day assessment with an optometrist or ophthalmologist. If in doubt, err on the side of being seen today.
- Sudden, painless vision loss in one eye: possible retinal artery occlusion — call 000/ED now.
- Eye injury or blunt trauma with blur or visible blood (hyphaema): ED same day.
- New significant blur, haze or many floaters: urgent same‑day review (possible vitreous haemorrhage or vein occlusion).
- Eye pain with reduced vision or light sensitivity: urgent assessment.
- Large or recurrent surface bleeds on blood thinners, or easy bruising/bleeding elsewhere: prompt medical review.
- Vision loss plus stroke‑like symptoms (face droop, slurred speech, weakness): call 000 immediately.
Subconjunctival haemorrhage (blood on the white of the eye)
Subconjunctival haemorrhage — often called a ‘blood clot in the eye’ — is the red patch on the white of the eye. It looks dramatic but is usually harmless, painless and doesn’t affect vision. Triggers include coughing, sneezing, straining, minor rubbing/trauma or blood thinners; risk rises with age, high blood pressure and diabetes. It clears in one to two weeks. Artificial tears can ease irritation; seek care if there’s pain, discharge, trauma or repeated episodes.
Hyphaema (blood pooling in front of the iris)
Hyphaema is blood pooling in front of the iris (the anterior chamber). It usually follows an eye injury and causes a visible reddish layer in the pupil area, often with pain, blurred vision and light sensitivity. Treat this as urgent: attend an emergency department the same day, especially after trauma. Until you’re seen, avoid rubbing and protect the eye. Recurrent episodes should be assessed promptly by an ophthalmologist.
Retinal vein occlusion (RVO)
Retinal vein occlusion is a blockage of the vein that drains blood from the retina — a type of “blood clot in the eye” that usually affects one eye. It typically causes painless, sudden or gradual blurring in one eye. Common risks include age, high blood pressure, diabetes and high cholesterol. This needs prompt same‑day assessment by an eye specialist. Treatment aims to protect sight by reducing macular swelling and preventing complications — often with intravitreal injections — and by addressing cardiovascular risks; laser may be used in selected cases.
Retinal artery occlusion (eye stroke): an emergency
Retinal artery occlusion is an eye stroke — a blockage of the artery that feeds the retina. It causes sudden, painless, severe vision loss in one eye. Treat it as an emergency: call 000 or attend the emergency department immediately, even if vision returns. Fast action offers the best chance to preserve sight and it also signals raised risk of a brain stroke.
- Rapid pressure‑lowering, ocular massage; sometimes paracentesis.
- Selected cases: clot‑dissolving medicines or hyperbaric oxygen.
- Stroke risk assessment for blood pressure, cholesterol and heart/arteries.
Vitreous haemorrhage and other eye bleeds
Vitreous haemorrhage is bleeding into the eye’s gel (vitreous). People notice a sudden shower of floaters or a haze with blurred vision; pain is uncommon. Common causes include diabetic eye disease, a retinal tear or detachment, and trauma. Get urgent assessment to rule out a tear or detachment. Treatment depends on cause — observation, laser to seal tears, targeted injections for diabetic bleeding, and in dense or non‑resolving cases, vitrectomy surgery. Other internal eye bleeds also warrant specialist review.
How specialists diagnose a "blood clot" in the eye
Your ophthalmologist will take a focused history (onset, trauma, medical conditions, medicines) and check vision, pupils and eye pressure. A surface bleed is usually obvious at the slit lamp, but deeper problems need a dilated retinal exam and imaging to pinpoint where bleeding or a blockage is and how much it threatens sight.
- Core examination: Visual acuity, eye pressure and slit‑lamp exam.
- Dilated retinal view: Fundus exam (ophthalmoscopy).
- Imaging: OCT and colour fundus photographs.
- Blood flow mapping: Fluorescein angiography.
- When needed: Ultrasound if the view is obscured; blood pressure check and, if indicated, blood tests or heart–vessel scans as part of an eye‑stroke work‑up.
Treatment options and what to expect
Treatment depends on where the bleeding or blockage is. Care ranges from reassurance and lubricants for surface bleeds to injections, laser or urgent procedures to restore flow and control pressure. Your ophthalmologist will also target cardiovascular risks that drive recurrence.
- Subconjunctival haemorrhage: Usually no treatment; artificial tears; check blood pressure if recurrent.
- Hyphaema: Emergency assessment; eye shield, rest; treat and monitor eye pressure.
- Vitreous haemorrhage: Observation or laser/injections; vitrectomy if dense or not clearing.
- Retinal vein occlusion: Intravitreal injections; selective laser; manage BP, cholesterol, diabetes.
- Retinal artery occlusion: Time‑critical; pressure‑lowering, massage/paracentesis; possible thrombolysis or hyperbaric oxygen; stroke work‑up.
Recovery time: how long it takes to heal
Recovery depends on where the “blood clot in the eye” is, how large it is, and how quickly you’re treated. A subconjunctival haemorrhage usually clears by itself in one to two weeks, fading like a bruise; larger patches can take a little longer. Hyphaema, vitreous haemorrhage and retinal vein occlusion often need active treatment and monitoring, with vision improving over time. Retinal artery occlusion is time‑critical; even with prompt care, some degree of vision loss may persist.
Prevention and reducing your risk of recurrence
You can’t prevent every eye bleed, but you can lower the chance of a “blood clot in the eye” returning by protecting the eye and addressing cardiovascular risks. If you’ve had a retinal artery occlusion, arrange a GP‑led stroke work‑up to reduce future events.
- Control risks: BP, cholesterol, diabetes; quit smoking.
- Be active: healthy weight, regular exercise.
- Reduce friction: avoid rubbing; lubricate dry eyes.
- Protect/meds: protective eyewear; review blood thinners with your GP.
Getting help in Sydney: referrals, costs and access
In Sydney, if you’re worried about a ‘blood clot in the eye’, arrange prompt assessment with an ophthalmologist. To access Medicare rebates, bring a current referral from your GP or optometrist (optometrists can send urgent referrals). Bright Sight Eye Specialists, led by Dr Rahul Dubey in Randwick, cares for patients across the Eastern Suburbs and rural NSW. Fees are transparent, with no‑gap cataract surgery options and most procedures offered as no GAP or known gap for insured patients. Ask when booking what costs apply to your situation.
Key takeaways
‘Blood clot in the eye’ ranges from harmless to urgent. Any vision change, pain or injury needs prompt review. Managing blood pressure, cholesterol and diabetes lowers risk.
- Bright red patch, no pain, vision normal: likely subconjunctival haemorrhage; clears in 1–2 weeks.
- Sudden, painless vision loss in one eye: suspected retinal artery occlusion — call 000.
- New blur, haze, many floaters or trauma‑related blood: get same‑day eye care.
In Sydney? Contact Bright Sight Eye Specialists for prompt assessment.