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Choroidal Neovascularization: Causes, Symptoms, and Treatment
Understanding Choroidal Neovascularization
CNV is a complex condition that begins deep within the layers of the eye. Learning how it forms and which conditions are linked to it can help you and your care team make informed decisions about monitoring and treatment.
The choroid is the layer of blood vessels that sits beneath the retina, the light-sensitive tissue lining the back of the eye. A thin barrier called Bruch membrane separates the choroid from the retinal pigment epithelium (RPE), a layer of cells that nourishes and supports the retina.
In CNV, abnormal new blood vessels grow out of the choroid and break through Bruch membrane. These vessels push into the space beneath or around the RPE and can extend under the macula, the central part of the retina responsible for sharp, detailed vision. Because the abnormal vessels are fragile and poorly formed, they tend to leak fluid and blood. This leakage causes swelling and scarring that can permanently damage central vision.
A protein called vascular endothelial growth factor (VEGF) plays a central role in CNV. VEGF promotes the formation of new blood vessels and is naturally present in the eye. However, when conditions such as tissue damage, reduced oxygen supply, or chronic inflammation disrupt the normal balance, VEGF production can increase dramatically.
Excess VEGF causes abnormal blood vessels to sprout and push through Bruch membrane. Once beneath the retina, these leaking vessels damage the photoreceptor cells that make central vision possible. The resulting fluid buildup and scarring are the primary causes of the vision loss seen in CNV.
Although CNV is most commonly associated with age-related macular degeneration (AMD), it can develop in the setting of several other eye conditions. Understanding the underlying cause helps guide treatment planning.
- Neovascular (wet) AMD, the most common cause of CNV in older adults
- Pathologic myopia, a form of severe nearsightedness in which the eye is structurally elongated and stretched
- Uveitis, or swelling and inflammation inside the eye
- Central serous chorioretinopathy, a condition where fluid collects beneath the retina
- Choroidal nevi, which are benign growths beneath the retina that can occasionally trigger abnormal vessel growth
Regardless of the underlying cause, the mechanism and treatment approach for CNV are often similar across these conditions.
Who Is at Risk for CNV?
CNV can affect people of different ages and backgrounds, though certain factors make some individuals more vulnerable than others. Identifying your personal risk factors is an important part of protecting your vision over time.
CNV most often develops as part of wet AMD, and advanced age is the strongest single risk factor for this form of the condition. Cigarette smoking significantly increases the likelihood of developing CNV, especially in people who already have AMD. Genetic factors, including variations in the immune system pathways that regulate inflammation, also appear to raise the risk.
If you have been diagnosed with dry AMD, your risk of progression to the wet form warrants ongoing monitoring even if your vision feels stable. Regular retinal examinations and imaging can detect CNV early, when treatment has the greatest chance of preserving sight.
Pathologic myopia is the most common cause of CNV in people under age 50. In pathologic myopia, the eyeball is significantly elongated, stretching and thinning the choroid and Bruch membrane. This mechanical stress can trigger the growth of abnormal vessels beneath the retina, even in relatively young adults.
The risk is not limited to those with extremely poor eyesight. Any patient with high myopia and a changing prescription should be aware that CNV can develop with little warning. Routine monitoring with optical coherence tomography (OCT) imaging is especially valuable for this group.
Central serous chorioretinopathy, a condition more common in younger men under stress, can progress to CNV in a meaningful subset of affected patients. Choroidal nevi located near the macula or the optic disc may also be associated with CNV, particularly when certain features are present, such as subretinal fluid, increased thickness, or orange pigment overlying the lesion.
Inflammatory eye conditions, including various forms of uveitis, can damage Bruch membrane and the RPE over time, creating conditions that favor abnormal vessel growth. Patients with any of these diagnoses benefit from regular retinal evaluations even when symptoms are absent.
Symptoms of Choroidal Neovascularization
CNV often produces noticeable changes in central vision that should never be dismissed or attributed to normal aging. Recognizing the warning signs early can make a significant difference in outcomes.
The most common early symptom of CNV is a distortion of central vision. Straight lines may appear wavy, bent, or irregular, a symptom called metamorphopsia. Some people notice that a section of their visual field looks blurry or washed out, particularly when looking directly at something.
Others experience a dark or blank area in the center of their vision, known as a central scotoma. Colors may appear less vivid in the affected eye. These changes often come on gradually at first but can worsen quickly as the abnormal vessels continue to leak.
Certain symptoms should prompt you to seek immediate evaluation from a retina specialist or visit an emergency setting without delay. Time-sensitive treatment is critical to preventing further damage when CNV is active.
- A sudden blur or darkening of central vision in one eye
- New wavy or crooked appearance to straight lines such as door frames, text, or tiles
- A dark or gray spot that appears at or near the center of what you are looking at
- A rapid change in vision that was previously stable
- Difficulty reading or recognizing faces that was not present before
Do not wait to see if these symptoms improve on their own. CNV can scar the macula within days to weeks if left untreated.
The macula contains the densest concentration of light-sensing photoreceptor cells in the entire retina. Once these cells are damaged by fluid, blood, or scar tissue from CNV, recovery is limited. The sooner treatment begins, the greater the chance of stabilizing or improving vision.
Monitoring your vision at home with an Amsler grid, a simple chart featuring a grid of horizontal and vertical lines, can help you detect changes between appointments. To use it, cover one eye, focus on the central dot, and look for any lines that appear wavy, missing, or distorted. Any change from your baseline should prompt an urgent call to your retina specialist.
How CNV Is Diagnosed
Diagnosing CNV requires a combination of clinical examination and specialized imaging. Our team uses the most current diagnostic tools to locate, measure, and characterize the abnormal vessels and assess any damage to the macula.
A comprehensive eye exam with pupil dilation is the starting point for evaluating suspected CNV. Dilating drops temporarily widen the pupil, giving the retina specialist a clear view of the retina, macula, and choroid. Active CNV may appear as a slightly elevated, grayish area beneath the macula. The specialist will also look for associated subretinal fluid, hemorrhage (bleeding beneath the retina), or scarring.
Optical coherence tomography (OCT) is a noninvasive imaging test that uses light waves to produce detailed, cross-sectional pictures of the retina. It is one of the most valuable tools for detecting and monitoring CNV. OCT can reveal fluid beneath or within the retina, thickening of the macula, and structural changes associated with abnormal vessel growth, often before symptoms become obvious.
OCT angiography (OCTA) is an advanced variation of this technology that maps blood flow within the retinal layers without the need for an injected dye. It provides detailed visualization of the CNV lesion itself and is increasingly used alongside traditional OCT to guide treatment decisions.
Fluorescein angiography is an imaging test in which a yellow dye is injected into a vein in the arm. As the dye circulates through the blood vessels of the eye, photographs are taken in rapid sequence. The test reveals exactly where vessels are leaking and helps identify the size, location, and classification of the CNV lesion. It remains one of the most informative diagnostic tests available for evaluating neovascularization.
Indocyanine green (ICG) angiography uses a different dye that is better suited to visualizing the deeper choroidal blood vessels. This test is particularly helpful when the type or extent of CNV is not fully clear from other imaging. It is often used alongside fluorescein angiography for a more complete picture of what is happening beneath the retina.
Treatment Options for CNV
Effective treatments for CNV exist and can preserve or even improve vision when started promptly. Treatment is individualized based on the type and extent of CNV, the underlying condition, and how your eye responds over time.
Anti-VEGF medications are currently the primary treatment for active CNV and are recommended as first-line therapy by leading ophthalmology organizations. These medications work by blocking VEGF, the protein responsible for driving abnormal blood vessel growth. When VEGF is suppressed, the leaking vessels can shrink and fluid can clear from the retina.
Anti-VEGF drugs are delivered by intravitreal injection, meaning they are injected directly into the vitreous, the gel-like substance that fills the inside of the eye. The procedure is performed in the office by a retina specialist. Before anti-VEGF therapy became available, most patients with CNV experienced steadily worsening vision. Today, many patients are able to maintain stable sight and a significant number see meaningful improvement with consistent treatment.
Several anti-VEGF medications are approved or commonly used for CNV. Each works by targeting VEGF, but they differ in their structure, dosing intervals, and approved indications. Your retina specialist will recommend the most appropriate option based on your specific diagnosis and circumstances.
- Ranibizumab was among the first anti-VEGF medications approved for both AMD-related CNV and myopic CNV and is typically given monthly
- Aflibercept is widely used and can often be extended to every 8 weeks or longer after an initial loading phase
- High-dose aflibercept is a formulation that may allow some patients to go up to 16 weeks between injections after loading doses
- Faricimab is a bispecific antibody that targets both VEGF-A and another pathway called angiopoietin-2, with potential for extended dosing intervals
- Bevacizumab is used off-label for CNV and has demonstrated effectiveness in clinical studies, though it is not FDA-approved for eye conditions
- Biosimilar versions of ranibizumab are FDA-approved and offer additional options for patients requiring long-term treatment
It is important to understand that anti-VEGF injections are a treatment for wet (neovascular) AMD and active CNV. They are not used for dry AMD in the absence of CNV.
Photodynamic therapy (PDT) uses a light-activated medication called verteporfin that is injected into a vein. A specialized laser is then directed at the abnormal blood vessels in the eye. The laser activates the drug within the target vessels, helping to seal them and reduce leakage. PDT was one of the first effective treatments for CNV and remains a useful option in specific situations, particularly for certain types of CNV that may not respond as well to anti-VEGF therapy alone. It is sometimes combined with anti-VEGF injections for a more comprehensive approach.
Intravitreal injections are performed in the office and typically take only a few minutes from start to finish. The eye is thoroughly cleaned and numbed with anesthetic drops before the injection. Most patients feel mild pressure during the procedure but do not experience significant pain.
After the injection, it is common to notice some mild redness, a sensation of grittiness, or temporary floaters in the treated eye. These effects typically resolve on their own within a day or two. Serious complications such as infection inside the eye, called endophthalmitis, are rare. However, any significant pain, rapidly worsening redness, or sudden decrease in vision after an injection should be reported to your retina specialist right away.
Treatment typically begins with a series of monthly loading injections, usually three in a row, to establish control over the CNV. After the loading phase, your retina specialist will determine the appropriate interval between treatments based on your individual response. OCT imaging is performed at each follow-up visit to assess fluid levels and the health of the macula.
Some patients eventually extend the time between injections to several months, while others require more frequent treatment. CNV is often a chronic condition that can reactivate after a period of stability. Keeping all scheduled appointments is essential because early detection of reactivation allows for prompt retreatment before additional vision is lost.
Living With Choroidal Neovascularization
Managing CNV extends beyond office visits and injections. Daily habits, home monitoring, and access to supportive resources all play a role in protecting and making the most of your vision.
Using an Amsler grid between appointments is one of the most practical steps you can take. This simple grid, available from your retina specialist or printable online, allows you to quickly check your central vision in each eye. Cover one eye, hold the grid at a comfortable reading distance, and focus on the center dot. If any lines appear wavy, blurry, or absent, contact your retina specialist promptly rather than waiting for your next scheduled visit.
Home monitoring is not a substitute for professional imaging and examination, but it gives you an active role in detecting changes early. Any new distortion should be treated as urgent.
While no lifestyle change can reverse CNV once it has developed, several habits may support overall retinal health and help reduce your risk of progression. Stopping smoking is one of the most impactful steps you can take, as smoking is strongly linked to AMD and CNV development. A diet rich in leafy green vegetables, colorful fruits, and omega-3 fatty acids found in fish may benefit retinal health over time.
Wearing sunglasses that filter ultraviolet light can help protect the eyes from cumulative sun damage. Managing cardiovascular risk factors such as high blood pressure may also support healthy circulation in the choroid. For patients with high myopia, regular retinal examinations are especially important since myopic CNV can develop without warning.
For patients who have experienced significant central vision loss from CNV, low vision rehabilitation can help maximize the functional vision that remains. Low vision specialists provide tools such as magnifying lenses, specialized lighting, electronic magnifiers, and adaptive technologies designed to make reading, writing, and other daily tasks more manageable. If you or a family member is struggling with vision loss from CNV, ask your retina specialist for a referral to a low vision program.
Frequently Asked Questions
These answers address common questions that go beyond what is covered in the sections above, offering practical guidance for patients navigating CNV diagnosis and treatment.
For most patients, CNV is a chronic condition that requires ongoing management rather than a one-time cure. Anti-VEGF therapy is highly effective at controlling abnormal vessel growth and clearing fluid from the retina, but the condition can reactivate even after years of stability. Some patients are eventually able to extend the time between treatments significantly, but very few can stop entirely without monitoring. Staying consistent with follow-up care is the most reliable way to protect your vision over the long term.
CNV is the biological process that defines wet AMD, but the two terms are not interchangeable across all patients. When CNV develops in someone who has AMD, that condition is classified as neovascular or wet AMD. However, CNV can also occur in younger patients with pathologic myopia, in those with inflammatory eye diseases, and in other clinical settings unrelated to AMD. The treatment approach with anti-VEGF therapy is broadly similar regardless of the underlying cause, though the dosing schedule and specific medication may vary.
Do not wait for your next scheduled appointment if you notice new or worsening distortion, a sudden darkening of central vision, or an increase in the blind spot in your visual field. These changes may indicate CNV reactivation that needs prompt evaluation and possibly earlier retreatment. Contact our office as soon as possible. If you cannot reach us quickly and symptoms are severe, an emergency visit to an eye clinic or hospital is appropriate.
Anti-VEGF injections have been used in retina care for many years and have a well-established safety profile. The most common side effects are mild and temporary, including redness at the injection site, brief discomfort, and transient floaters. Serious complications such as infection inside the eye or a torn retina are possible but uncommon when procedures are performed with appropriate technique and antiseptic precautions. Your retina specialist will review the risks and benefits with you before starting treatment and will monitor for any side effects at each visit.
Delaying treatment for active CNV is generally not recommended. Unlike some retinal conditions that can be monitored conservatively, active CNV with leaking vessels and fluid under the macula tends to cause progressive damage. Each week of active disease increases the risk of permanent scarring. If your retina specialist recommends treatment, beginning it promptly gives you the best chance of preserving your current level of vision and possibly regaining some of what has been lost.
All four of our offices offer the full range of diagnostic and treatment services for CNV, including anti-VEGF injections and OCT imaging. You are welcome to be seen at whichever location is most convenient for you, whether that changes from appointment to appointment or stays consistent. Our team coordinates care seamlessly across locations so that your treatment plan remains continuous regardless of which office you visit.
Schedule Your Evaluation at New England Retina Associates
If you have been diagnosed with CNV, referred by your eye doctor, or are experiencing changes in your central vision, we encourage you to schedule a consultation with our team at New England Retina Associates. Our fellowship-trained vitreoretinal surgeons bring deep expertise and a compassionate approach to every patient they see, and we are committed to providing the most current and effective care available. We welcome self-referred patients, urgent referrals, and those seeking a second opinion at any of our four convenient offices throughout Connecticut. We are here to help you protect your vision and navigate your care with confidence.
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