- Medically Reviewed by: Mr Mfazo Hove, Consultant Ophthalmic Surgeon
- Author: Mr Mfazo Hove
- Published: July 16, 2026
- Last Updated: July 16, 2026
In short. Retinal vein occlusion happens when a vein draining the retina becomes blocked, causing sudden, usually painless blurring or loss of vision in one eye. It is often linked to blood pressure, diabetes and circulation, so it needs both eye treatment and a general health check. Sudden vision change in one eye warrants prompt specialist assessment.
The Blue Fin Vision® Rapid Medical Retina Pathway
- Prompt consultant-led assessment
- OCT imaging
- Diagnosis: wet AMD, dry AMD, RVO, CRVO or another retinal cause
- Intravitreal injection where appropriate
- Communication with your GP and optometrist on blood pressure, diabetes and vascular risk
- Ongoing monitoring, with escalation to Professor Mahmut Dogramaci, Consultant Vitreoretinal Surgeon, where needed
What Retinal Vein Occlusion Is, and Its Symptoms
Retinal vein occlusion (RVO) occurs when one of the veins carrying blood away from the retina becomes blocked, causing blood and fluid to back up¹. This can lead to swelling at the macula (macular oedema) and sudden, painless loss or blurring of vision in the affected eye¹. RVO is the second most common retinal vascular disorder, affecting an estimated 28 million people worldwide², and it becomes more common with age³.
Retinal Vein Occlusion Causes
A retinal vein occlusion is, in effect, a clot (thrombosis) in a vein of the retina¹. In branch occlusions the blockage usually happens where a stiffened artery crosses and presses on a vein, because the two share a common sheath; in central occlusions the blockage is at the main vein as it leaves the eye through the optic nerve⁴. Three factors combine to cause it: changes in the vessel wall, often from high blood pressure and atherosclerosis; sluggish blood flow; and a tendency of the blood to clot¹.
In people over about 50, the usual drivers are high blood pressure, diabetes, raised cholesterol and glaucoma². In younger patients, less common causes such as clotting disorders, inflammatory conditions and the combined oral contraceptive pill are considered, which is why a broader work-up is sometimes needed⁴.
Why It Is Also a General Health Matter
RVO is closely linked to the health of your blood vessels. High blood pressure is the strongest risk factor², and diabetes, raised cholesterol, glaucoma and clotting tendencies also contribute¹. For this reason, Blue Fin Vision® treats the eye and, working with your GP, makes sure the underlying factors such as blood pressure and blood sugar are checked and managed. Treating the eye without addressing these risks would miss half the picture.
Two parts to good RVO care
Eye treatment: OCT monitoring, anti-VEGF injections for macular oedema, and laser in selected cases. Health checks: blood pressure, diabetes, cholesterol, smoking, glaucoma and cardiovascular risk, with selected clotting tests depending on your age and history.
Retinal Vein Occlusion Treatment Options
The main threat to vision in RVO is macular oedema, and this is highly treatable. Anti-VEGF injections into the eye reduce the swelling and improve vision in many patients⁵. Options include aflibercept, ranibizumab and faricimab, and your specialist will advise which is appropriate. Laser treatment has a role in some cases, particularly where abnormal new vessels develop, and some milder cases are monitored⁴. OCT scanning guides treatment and follow-up.
The Blue Fin Vision® Pathway
Our medical retina service offers rapid-access assessment with OCT so that a sudden change is investigated quickly, and treatment is started without delay where appropriate. Complex vitreoretinal care and escalation are led by Professor Mahmut Dogramaci, Consultant Vitreoretinal Surgeon. Injections are delivered at The Harley Street Eye Centre, our dedicated London setting for private intravitreal injection care, with selected hospital sites available where clinically appropriate, which may involve additional cost.
Long-Term Effects
The outlook depends on the type and severity of the occlusion and on how much the central retina is affected⁶ ⁷. The main long-term problems are persistent or recurrent macular oedema, which needs ongoing treatment; macular ischaemia, where the small vessels close and central vision is permanently reduced; and, in more severe (ischaemic) cases, the growth of abnormal new vessels that can cause vitreous haemorrhage or a difficult form of glaucoma⁴. Careful monitoring is designed to catch these early. Because the same blood-vessel risks affect the whole body, retinal vein occlusion is also a marker of higher cardiovascular and stroke risk, which is a further reason to manage blood pressure and general health¹.
How Many Injections Might I Need?
Vein occlusion usually needs more intensive treatment early on. After initial monthly injections to bring the swelling down, the interval is gradually extended using a treat-and-extend approach⁵. As a realistic guide, many people need in the region of 6 to 10 injections in the first year, with fewer in the second year as the eye stabilises, so somewhere around 10 to 15 over two years is common. This varies widely: milder branch occlusions may need far fewer, while some eyes need continued regular treatment. Your consultant gives you a tailored estimate once your eye’s response is clear.
Frequently Asked Questions
Is retinal vein occlusion painful?
Usually not. The typical sign is sudden, painless blurring or loss of vision in one eye¹, which is why it can be missed until checked.
Can vision recover?
Many people regain useful vision with prompt anti-VEGF treatment of the macular swelling⁵, though outcomes depend on the type and severity.
Why do I need a blood-pressure and diabetes check?
Because RVO is strongly linked to these conditions². Managing them protects the other eye and your general health.
How urgently should I be seen?
Promptly. Sudden vision change in one eye should be assessed quickly so that treatable macular swelling is not left.
What is the difference between branch and central RVO?
A branch occlusion blocks a smaller vein and affects part of the retina; a central occlusion blocks the main vein and tends to be more serious.
For sudden or unexplained blurring in one eye, book a prompt medical retina assessment with OCT imaging and specialist advice.
Related Pages
References
- Wong TY, Scott IU. Retinal vein occlusion. N Engl J Med. 2010;363(22):2135-2144.
- Song P, Xu Y, Zha M, Zhang Y, Rudan I. Global epidemiology of retinal vein occlusion: a systematic review and meta-analysis of prevalence, incidence, and risk factors. J Glob Health. 2019;9(1):010427.
- Rogers SL, McIntosh RL, Cheung N, Lim L, Wang JJ, Mitchell P, Kowalski JW, Nguyen H, Wong TY. The prevalence of retinal vein occlusion: pooled data from population studies from the United States, Europe, Asia, and Australia. Ophthalmology. 2010;117(2):313-319.e1.
- Scott IU, Campochiaro PA, Newman NJ, Biousse V. Retinal vascular occlusions. Lancet. 2020;396(10266):1927-1940.
- Brown DM, Campochiaro PA, Singh RP, Li Z, Gray S, Saroj N, Rundle AC, Rubio RG, Murahashi WY; CRUISE Investigators. Ranibizumab for macular edema following central retinal vein occlusion: six-month primary end point results of a phase III study. Ophthalmology. 2010;117(6):1124-1133.
- McIntosh RL, Rogers SL, Lim L, Cheung N, Wang JJ, Mitchell P, Kowalski JW, Nguyen HP, Wong TY. Natural history of central retinal vein occlusion: an evidence-based systematic review. Ophthalmology. 2010;117(6):1113-1123.e15.
- Central Vein Occlusion Study Group. Natural history and clinical management of central retinal vein occlusion. Arch Ophthalmol. 1997;115(4):486-491.
ABOUT THE AUTHOR
Mr Mfazo Hove
Consultant Ophthalmic Surgeon
MBChB MD FRCOphth CertLRS
Mr Mfazo Hove is a Consultant Ophthalmic Surgeon with experience spanning more than 57,000 procedures. He completed 6.5 years of specialist training at Moorfields Eye Hospital and served for five years as a consultant at the Western Eye Hospital, Imperial College Healthcare NHS Trust. He is the founder of Blue Fin Vision®, a consultant-led private ophthalmology practice operating across London, Essex, and Hertfordshire. His clinical expertise encompasses advanced cataract surgery, refractive lens replacement, laser vision correction, and implantable Collamer lenses (ICL).
A ZEISS Key Opinion Leader, Mr Hove is a respected international speaker with five invited engagements across seven cities in 2026:
- ZEISS China tour (Changsha, Shanghai, and Hangzhou, April – ZEISS APAC User Meeting)
- RCOphth Annual Congress – May – Manchester
- ZEISS EMEA User Meeting (Istanbul)
- ZEISS Lausanne User Meeting (Lausanne)
- European Society of Cataract and Refractive Surgeons Annual Congress (ESCRS, London)
