A sudden blur in one eye may be more than a change in eyesight. It could be a sign of retinal vein occlusion, a condition where blood flow out of the retina becomes blocked.
Retinal vein occlusion (RVO) is a common retinal vascular disorder that can cause blurred vision, swelling and bleeding inside the retina. It is seen more frequently in people over 50, particularly those with high blood pressure, diabetes, high cholesterol or glaucoma.
Although the blockage itself is not usually removed directly, treatments such as retinal injections and laser can help manage its complications and protect vision.
If you experience sudden, painless blurring or loss of vision in one eye, seek urgent medical assessment.
What Is Retinal Vein Occlusion, and What Are the Types of Retinal Vein Occlusion?
Retinal vein occlusion occurs when one of these veins becomes blocked, preventing blood from draining normally
Branch RVO (BRVO) | Central RVO (CRVO) | |
Where the blockage is | A branch vein, usually where an artery crosses it | The main vein behind the optic nerve head |
Part of the retina affected | One section | The whole retina |
How common | About 0.64% of adults aged 30 to 89 | About 0.13% of adults aged 30 to 89 |
Typical effect on vision | A patch of blurred vision, or no symptoms | Sudden, more widespread blurring |
Prevalence: Song et al., 2019, Journal of Global Health. Only a retinal examination can confirm the type.
What Are the Symptoms of Retinal Vein Occlusion?
- Sudden blurred vision in one eye: Usually painless. Vision may be mildly or severely reduced.
- A dark or blurred patch in part of the vision: Common with a branch occlusion.
- Distorted central vision: Straight lines may look wavy when swelling reaches the macula, the centre of the retina.
- New floaters: Dark spots or a haze if bleeding spreads into the vitreous gel.
- No symptoms at all: A small branch occlusion may only be found on a routine eye examination.
What Causes Retinal Vein Occlusion?
Most cases are caused by a blood clot or compression inside a retinal vein.
- At an artery-vein crossing
Arteries and veins share a sheath where they cross. A hardened artery can press on the vein and trigger a clot, the usual cause of branch occlusion. - Behind the optic nerve head
A hardened central artery can compress the central vein beside it. - Slow blood flow, vessel wall damage and a tendency to clot
Together, these make a clot more likely. - Raised eye pressure
Glaucoma can impair drainage from the retina. - Changes Associated With High Blood Pressure
In some patients, no single cause is found.
What Are the Risk Factors for Retinal Vein Occlusion?
A 2019 global meta-analysis of population studies in adults aged 30 to 89, published in the Journal of Global Health, linked RVO most strongly with:
- High blood pressure
- A previous heart attack
- A previous stroke
- Age
- Higher cholesterol
Other recognised risk factors include
- Glaucoma,
- Diabetes (particularly for central occlusion),
- Smoking,
- Blood clotting disorders and conditions that thicken the blood.
Because RVO shares its risk factors with heart disease and stroke, it is also a reason to have blood pressure and cholesterol checked.
What Are the Other Complications of Retinal Vein Occlusion?
- Macular oedema
Fluid swelling in the macula. The main cause of vision loss in RVO.
- Macular ischaemia
Poor blood flow to the macula itself, which can limit how much vision recovers.
- Neovascular glaucoma
New vessels on the iris block the eye’s drainage channels and sharply raise eye pressure.
- Vitreous haemorrhage
Bleeding from fragile new vessels into the vitreous gel, seen as sudden floaters or a haze.
These complications can appear after vision has started to settle. Follow-up timing depends on the type of occlusion and how much of the retina has lost its blood supply.
How Is Retinal Vein Occlusion Diagnosed?
- Symptom history and vision test
- Eye pressure check, including the drainage angle, for new vessels
- Dilated retinal examination to see bleeding, swollen veins and cotton-wool spots
- OCT scan to measure macular swelling and track the response to treatment
- Fluorescein angiography, a dye test showing which areas have lost blood flow
- General health checks: blood pressure, blood sugar, cholesterol and blood counts, with clotting tests for younger patients or occlusions in both eyes
Together, these findings decide whether treatment is needed now, and which one.
How Is Retinal Vein Occlusion Treated?
No treatment reopens the blocked vein. Treatment targets the complications that threaten vision.
- Anti-VEGF injections
Medicines injected into the eye to reduce macular swelling and new vessel growth. Usually the first choice for macular oedema.
- Steroid implant
A slow-release dexamethasone implant, often used when swelling does not respond well to injections.
- Laser photocoagulation
Grid laser for macular swelling in selected branch occlusions; scatter laser for areas of poor blood flow.
- Vitrectomy
Surgery for bleeding that does not clear or for retinal detachment. - Control of risk factors
Blood pressure, blood sugar, cholesterol and smoking, managed with your physician.
If My Vision Is Better, Can I Skip My Next Injection?
Not without discussing it with your retina specialist.
Vision can improve while retinal swelling is still present, and fluid can recur after an initially good response.
How Many Retinal Injections Are Needed for RVO?
This is one of the most common questions patients ask.
There is no fixed number of injections that works for every patient.
Some patients respond relatively quickly, while others require repeated treatment over months or longer.
Retinal Vein Occlusion Care at AKIO: Retina Specialist in Delhi
Medical Director and Padma Shri awardee Dr Atul Kumar leads AKIO’s retina team, with 41+ years of retinal expertise and experience as former Chief of the Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi.
Dr Aman Kumar, Senior Consultant Vitreo-Retinal and Cataract Surgeon, is an AIIMS New Delhi alumnus and PGIMER Chandigarh Gold Medallist whose work includes macular disorders, diabetic retinopathy and retinal surgery.
AKIO manages retinal vein occlusion with OCT and widefield retinal imaging, intravitreal injections, laser photocoagulation and vitrectomy, chosen according to the type of occlusion and its complications.
Advice from AKIO’s retina team after a retinal vein occlusion
- Keep every follow-up visit, even if vision feels stable. New vessels can develop without symptoms.
- Have blood pressure, blood sugar and cholesterol controlled with your physician.
- Report new floaters, a dark shadow, eye pain or redness immediately.
- Have the other eye examined, as its risk factors are the same.
For patients looking for a retina specialist in Delhi after sudden blurring in one eye, the first step is a dilated retinal examination and OCT scan to confirm the type of occlusion and whether the macula is swollen.
Sudden, painless loss of vision in one eye needs immediate assessment. Contact AKIO for retinal emergencies.
About the Author: Dr Aman Kumar
Dr Aman Kumar is a Senior Consultant Vitreo-Retinal and Cataract Surgeon at AK Institute of Ophthalmology (AKIO), New Delhi. He is an alumnus of AIIMS New Delhi and a Gold Medallist from PGIMER Chandigarh, where he completed his MS and then did his senior residency at the Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS. His clinical work covers complex retinal conditions, including retinal detachment, diabetic retinopathy, macular disorders, and uveitis. He performs 3D vitreoretinal surgery and micro-incision cataract surgery.
Frequently Asked Questions
Is retinal vein occlusion curable?
No treatment reopens the blocked vein. Its complications can be treated, and many patients keep or regain useful vision with timely care.
What are the main causes of retinal vein occlusion?
A blood clot or compression inside a retinal vein, most often linked to high blood pressure, high cholesterol, glaucoma, diabetes and age over 50.
What are the treatment options for retinal vein occlusion?
Anti-VEGF injections, steroid implants, laser photocoagulation and, for bleeding or detachment, vitrectomy. The choice depends on the type of occlusion and its complications.
How common is retinal vein occlusion?
It affects about 0.77% of adults aged 30 to 89, roughly 28 million people worldwide, according to a 2019 global meta-analysis.
How long is retina surgery recovery?
Recovery after vitrectomy usually takes several weeks, and vision can keep improving for months. Your retina surgeon will advise on positioning and activity.
Can retinal vein occlusion affect the other eye?
It usually affects one eye. The other eye shares the same risk factors, so it should be examined and those risk factors controlled.
Can I travel for retinal vein occlusion treatment?
Yes. Travel by air, car or train to see a retina specialist is not restricted. Flying is only restricted after surgery while a gas bubble remains in the eye.
Are retinal injections painful?
Intravitreal injections are generally performed using anaesthetic drops or other local anaesthesia.
Can retinal vein occlusion affect the other eye?
Yes, although RVO commonly affects one eye. The other eye may share vascular risk factors and should be examined as advised.
