Choroidal neovascularization (CNV) is a serious eye condition characterized by abnormal blood vessel growth, impacting your vision. Early detection is key to effective management and preserving sight. Find a top optometrist or ophthalmologist near you to discuss your symptoms today.
Choroidal neovascularization, or CNV, is the abnormal growth of fragile blood vessels in the choroid—a vital, blood-rich layer located between the sclera and the retina. This condition can lead to the leakage of fluids and blood, which may damage the retina and ultimately result in vision loss. Understanding CNV is important because early detection and care can help maintain your vision and quality of life.
As of 2025, an estimated 58,000 adults in the United States are affected by myopic choroidal neovascularization (CNV), based on a prevalence rate of 0.017% and current national population data.
Choroidal neovascularization (CNV) is a condition where abnormal new blood vessels grow from the choroid, the vascular layer beneath the retina responsible for delivering oxygen and nutrients to its outer layers. In a healthy eye, this process is tightly regulated. However, when that balance is disrupted, these new vessels form inappropriately.
These abnormal vessels are fragile and prone to leaking fluid or blood, which can disrupt the delicate structure of the retina. This leakage can damage photoreceptor cells—the rods and cones responsible for capturing light—leading to blurred vision, distortion, and other visual disturbances.
One of the challenges of CNV is that its onset is often painless, and the early signs might not significantly disrupt daily activities. Here’s the thing: vision changes can happen gradually, and patients sometimes notice them only when the condition has advanced. The following symptoms are common indicators of choroidal neovascularization:
The quality of your central vision might start to fade, appearing dim or out of focus.
A dark or blank area may form near or in the center of your vision.
Straight lines may seem warped or wavy, altering the clarity of patterns and shapes.
Your ability to see colors may be affected, making them look off or less vivid.
Some patients report the sensation of lights intermittently flickering in the center of their view.
If you experience any sudden or unusual changes in your vision, it’s important to seek medical attention right away. Signs to watch for include:
These symptoms may signal the onset or progression of choroidal neovascularization (CNV). Because CNV often develops silently and painlessly, many people delay seeking care—sometimes until irreversible damage has already occurred.
The development of choroidal neovascularization is often linked to underlying conditions that compromise the eye’s delicate structure. One of the most significant causes is the progression from dry to wet age-related macular degeneration (AMD). In cases of dry AMD, the retina gradually loses its thickness and the accumulation of drusen, which are protein clumps around the macula, sets the stage for more advanced disease. When these changes lead to the development of CNV, the condition escalates to wet AMD and requires immediate attention.
Furthermore, conditions that disrupt the integrity of Bruch’s membrane—the barrier between the retina and the choroid—can lead to the development of CNV. In cases of trauma or injury, whether from accidental damage or following procedures like laser surgery, this barrier can be compromised. The resulting breach allows VEGF to stimulate the growth of abnormal vessels, prompting the cascade of events that result in CNV.
Other risk factors include chronic inflammatory conditions, such as sarcoidosis, and degenerative changes associated with high myopia. When the eye undergoes structural changes due to severe myopia, the risk of developing myopic macular degeneration increases, which in turn raises the likelihood of choroidal neovascularization. Keeping an eye on these risk factors and managing them through lifestyle adjustments and regular eye exams can be crucial in reducing your risk.
CNV is most notably associated with wet age-related macular degeneration (AMD), the more severe form of macular degeneration. While dry AMD is more common and tends to progress slowly, about one in ten people with dry AMD eventually develop CNV, leading to wet AMD. Wet AMD is characterized by its rapid onset and significant vision loss due to the leakage of fluid and blood.
Aside from AMD, CNV can also develop from a variety of other conditions that compromise the integrity of the eye’s protective layers:
Any injury to the choroid, whether due to external trauma or as a result of a surgical procedure like laser treatment, can disrupt the barrier between the choroid and the retina.
These are breaks in the elastic fibers of Bruch’s membrane that can predispose the eye to abnormal vessel growth.
In high myopia, where the shape of the eye is elongated, degenerative changes can affect the retina and choroid, making CNV more likely.
This condition, linked to a fungal infection, can lead to scar formation and neovascularization in the choroid.
Diseases such as sarcoidosis can lead to inflammatory changes in the eye, contributing to the formation of abnormal vessels.
Although rare, tumors in the choroid can cause damage that triggers CNV.
Fluorescein angiography is a detailed test in which a special dye is injected into your arm. This dye circulates through the bloodstream and makes its way to the blood vessels in your eyes. As the dye lights up the vessels, images are captured that clearly show areas where there is leakage from abnormal blood vessels. This method is especially useful in distinguishing between different types of choroidal neovascular membranes (CNVM), often categorized as occult (type 1) or classic (type 2) based on their appearance.
This test not only helps in identifying the location of CNV but also provides insights into the severity of fluid leakage, offering guidance on potential treatment methods.
If you notice any of the symptoms of choroidal neovascularization, don’t wait. Contact Dr. Smith or our team of retina specialists today to schedule a comprehensive eye exam and explore treatment options that can help preserve your vision.
Optical coherence tomography is a painless imaging procedure that produces high-quality, three-dimensional cross-sectional images of the retina. Unlike fluorescein angiography, OCT does not require any injections. Instead, it uses light waves to capture detailed images of the retinal layers, highlighting any abnormalities such as the presence of a choroidal neovascular membrane.
By analyzing these images, our retina specialists can evaluate the extent of retinal damage caused by CNV, monitor changes over time, and tailor treatment plans to the specific needs of each patient.
It’s important to note that the choice of treatment depends on factors such as the location and type of choroidal neovascular membrane, as well as the overall condition of the eye. Our retina specialists are thorough in determining the best course of action for each patient.
Since excessive production of VEGF is a known driver behind CNV, anti-VEGF therapy has become a cornerstone in its treatment. In this procedure, anti-VEGF drugs are injected directly into the eye to block the effects of the excess VEGF. This helps to slow the growth of abnormal blood vessels and decrease the leakage of fluid and blood.
Multiple injections are often required over time to manage the condition effectively. Anti-VEGF treatment can stabilize vision and, in some cases, even lead to visual improvements. It is important to adhere closely to follow-up visits and treatment schedules, as guided by our retina specialists.
Photodynamic therapy combines a light-activated drug with a low-energy laser to target the leaky blood vessels in CNV. A drug is injected into the bloodstream, which then concentrates in the areas where abnormal blood vessels show signs of leakage. When a low-energy laser is applied, it activates the drug and helps to damage these vessels, reducing the leakage of both fluid and blood.
PDT is especially useful in cases where anti-VEGF therapy alone may not be enough. It provides another option for controlling the progression of CNV and protecting the integrity of the retina.
Laser photocoagulation is a treatment that uses a high-energy laser to create a small, precise burn in the area of abnormal blood vessels. This burn essentially seals off the problematic vessels, preventing further leakage and reducing damage to the surrounding retinal tissue. While this method is less frequently used than anti-VEGF or PDT, it can be effective in specific scenarios where the abnormal vessels are well-defined and accessible.
While not every case of CNV can be prevented, there are lifestyle changes that can help reduce the risk of developing this challenging condition. Our retina specialists suggest that certain habits might lower the risk, especially for individuals predisposed to conditions like AMD:
Quitting smoking is one of the most important steps you can take, as smoking has been linked to the progression of macular degeneration and the development of CNV.
Consuming a diet rich in antioxidants, fruits, and vegetables can support overall eye health. Foods high in vitamins C and E, as well as omega-3 fatty acids, have been associated with a lower risk of eye-related conditions.
Maintaining a healthy lifestyle through regular physical activity can improve blood circulation, which may benefit eye health.
Keeping your weight in check is beneficial for your eyes and your overall well-being.
Wearing sunglasses with UV protection can help shield your eyes from harmful ultraviolet rays when you’re outdoors.
If you notice any of the symptoms of choroidal neovascularization, don’t wait. Contact Dr. Smith or our team of retina specialists today to schedule a comprehensive eye exam and explore treatment options that can help preserve your vision.
Choroidal neovascularization (CNV) causes abnormal blood vessel growth in the eye, leading to vision loss. Learn about symptoms, causes, and treatments.
