Central Retinal Vein Occlusion: Causes, Symptoms, and Treatment

The most common symptom of CRVO is a noticeable change in vision in one eye. This may come on suddenly or worsen over several hours or days. Vision may appear blurry, dim, or distorted, and in some cases the vision loss can be severe. Most cases of non-ischemic CRVO cause painless vision loss, meaning there is no discomfort despite the visual change.

Some patients notice floaters, which are dark spots, threads, or squiggly shapes that drift across the visual field. Floaters associated with CRVO are shadows cast by tiny amounts of blood that have leaked from damaged retinal vessels into the vitreous, the clear gel that fills the interior of the eye. These shapes move with eye movement, which distinguishes them from fixed visual defects.

Pain and pressure in the affected eye are less common in early CRVO but can develop as complications arise. Severe ischemic CRVO can trigger the growth of abnormal new blood vessels on the iris (the colored part of the eye) and elsewhere inside the eye. When these abnormal vessels obstruct the eye's drainage system, they can cause neovascular glaucoma, a serious condition that raises eye pressure and produces significant pain, redness, and further vision loss.

If you experience sudden vision loss, a sudden increase in floaters, flashes of light, or pain in one eye, seek immediate care from a retina specialist or emergency eye care provider. These symptoms should never be ignored or watched over time.

Before each injection, the eye is numbed with anesthetic drops and cleaned with an antiseptic solution. The injection itself takes only a few seconds. Most patients feel mild pressure or a brief sensation during the procedure, but significant pain is uncommon. You may notice some temporary cloudiness or floaters in the hours after an injection as the medication disperses through the eye.

Visual outcomes vary based on the type of CRVO, the degree of retinal damage, how quickly treatment began, and individual patient factors. Patients with non-ischemic CRVO generally have a better prognosis than those with the ischemic form. Anti-VEGF therapy has substantially improved outcomes for CRVO patients compared to earlier eras when effective treatments were not available, but complete visual recovery is not guaranteed for every patient.

Many patients require ongoing injections to keep macular edema under control. Stopping treatment too early can allow swelling to return and lead to further vision loss. Your specialist will use imaging and vision testing at each visit to determine the right frequency of care for your specific situation.

Regular follow-up visits are essential after a CRVO diagnosis. At each appointment, your retina specialist will check your visual acuity, perform OCT imaging to measure retinal swelling, and assess for signs of new vessel growth or other complications. Because non-ischemic CRVO can progress to the ischemic form over time, monitoring continues even when your initial presentation is mild. Your specialist will adjust your treatment plan as your retina changes.

CRVO almost always affects only one eye at a time. However, having a CRVO in one eye does increase the risk of developing the condition in the other eye, particularly if underlying conditions such as high blood pressure or diabetes remain uncontrolled. Attending all scheduled follow-up visits and actively managing systemic risk factors are the most effective ways to protect your other eye. Notify your retina specialist right away if you notice any new visual symptoms in your unaffected eye, no matter how subtle they seem.

There is no universal answer to this question. Some patients require injections for many months or even years to maintain control of macular edema, while others find that the condition stabilizes enough to allow longer intervals between treatments over time. Your retina specialist uses OCT imaging and vision testing at every visit to assess whether your treatment schedule can safely be extended or whether it should remain frequent. The goal is always to find the least frequent schedule that keeps your retina stable and your vision protected.

Visual recovery depends on the type of CRVO you have, the degree of retinal damage that occurred before treatment began, and individual factors that vary from person to person. Many patients experience meaningful vision improvement with anti-VEGF therapy, but recovering fully to pre-CRVO levels is not guaranteed, particularly with ischemic CRVO or when treatment is delayed. Starting treatment promptly and attending all follow-up visits give you the best possible chance of preserving and improving your vision over time.

CRVO shares many of the same underlying risk factors as heart disease and stroke, including high blood pressure, diabetes, and atherosclerosis. Research has found that patients with CRVO have a statistically elevated risk of cardiovascular events even after known risk factors are accounted for. For this reason, a CRVO diagnosis often warrants a thorough cardiovascular evaluation by your primary care doctor or a cardiologist. Treating CRVO as a signal to review your overall vascular health is a prudent and potentially life-saving step.

There is no guaranteed way to prevent CRVO, but you can meaningfully lower your risk through lifestyle and medical management. Keeping blood pressure and blood sugar in healthy ranges, maintaining good cholesterol levels, avoiding smoking, and having regular dilated eye exams are all protective measures. If you have a known blood clotting disorder, working with your doctor to manage it appropriately is equally important. These steps benefit not only your retinal health but your cardiovascular health more broadly.

Central retinal vein occlusion involves a blockage of the single main vein that drains the entire retina, while branch retinal vein occlusion (BRVO) involves a blockage of a smaller branch vessel serving only a portion of the retina. CRVO tends to produce more extensive vision changes because the whole retina is affected, while BRVO typically affects a more limited area of vision. Both conditions are diagnosed and treated by retina specialists, and the treatment approaches overlap considerably, though their prognoses and monitoring needs differ based on the extent of involvement.