Neovascular macular degeneration, often called wet age-related macular degeneration (AMD), is a serious eye condition that impacts central vision. It is a progressive disease, meaning symptoms can worsen over time. While it is less common than the “dry” form of AMD, neovascular AMD accounts for about 90% of severe vision loss associated with the condition. It primarily affects older adults and is a leading cause of vision impairment globally.
Understanding Neovascular Macular Degeneration
The eye’s retina, a light-sensitive tissue at the back of the eye, contains a specialized area called the macula. The macula is responsible for sharp, detailed central vision, necessary for tasks like reading and recognizing faces.
In neovascular macular degeneration, abnormal blood vessels begin to grow beneath the macula, a process known as neovascularization or choroidal neovascularization (CNV). These new blood vessels are often fragile and prone to leaking.
When these vessels leak fluid or blood, it accumulates under or within the macula, causing swelling and damage. This fluid buildup can distort the macula’s shape, affecting its ability to process images clearly. Over time, this leakage can lead to the formation of scar tissue, resulting in significant central vision loss. The presence of these leaky vessels is why the condition is often referred to as “wet” AMD, distinguishing it from the “dry” form.
Recognizing the Signs
Individuals with neovascular macular degeneration may experience a range of symptoms, which can sometimes appear suddenly and progress quickly. One common symptom is distorted straight lines, where lines that should appear straight instead look wavy or bent, often detected using an Amsler grid.
Reduced central vision in one or both eyes is another frequent complaint, making it difficult to see objects directly in front of them. People may also find they need brighter light for reading or close-up work, and they might have trouble adjusting to low-light environments.
Printed words can become blurry, and recognizing faces may become challenging. Some individuals report a well-defined blurry spot or a blind spot in their central field of vision, and colors may appear less vibrant or intense. Prompt medical attention is important if any of these changes are noticed, as early intervention can help slow the progression of vision loss.
Factors Increasing Risk
Age is the most significant risk factor for developing neovascular macular degeneration, with the condition becoming more prevalent in individuals over 50. The risk increases notably after age 75. Genetics also play a role, meaning a family history of macular degeneration can increase an individual’s likelihood of developing the condition.
Lifestyle choices and other health conditions also contribute to the risk. Smoking cigarettes significantly elevates the risk, with smokers being up to four times more likely to develop AMD than non-smokers. Obesity may increase the chance of dry AMD progressing to the more severe wet form.
Conditions affecting cardiovascular health, such as high blood pressure and high cholesterol, are also associated with an increased risk of neovascular AMD. A diet low in fruits and vegetables is linked to a higher risk, while diets rich in these foods, like Mediterranean or Oriental diets, may lower the risk.
Detection and Treatment
Detecting neovascular macular degeneration begins with a comprehensive eye exam. During this exam, the doctor will look for signs of the condition, such as drusen or abnormal blood vessels.
The Amsler grid test is a simple tool where patients look at a grid of straight lines and report any distortions, blurriness, or blank spots, which can indicate macular damage. Optical coherence tomography (OCT) is a non-invasive imaging test that uses light waves to create cross-sectional images of the retina, allowing the doctor to visualize fluid accumulation or swelling beneath the macula. Optical coherence tomography angiography (OCTA) is a newer method that uses laser light reflection to produce 3D images of blood flow, identifying abnormal vessels without the need for dye. Fluorescein angiography (FA) involves injecting a special dye into the bloodstream, which travels to the eye and highlights leaky blood vessels as images are taken, revealing the location and extent of neovascularization.
The primary treatment for neovascular macular degeneration involves anti-VEGF (anti-vascular endothelial growth factor) injections. VEGF is a protein that promotes the growth of new, abnormal blood vessels and increases their leakage.
Anti-VEGF medications work by blocking this protein, inhibiting blood vessel growth and reducing fluid leakage. These medications are administered directly into the eye by a retina specialist, requiring multiple injections over time, often monthly initially, to stabilize vision and reduce disease activity. While anti-VEGF injections aim to slow disease progression and preserve existing vision, they do not restore vision that has already been lost. Less common or older treatments, such as photodynamic therapy (PDT) and laser photocoagulation, are now used infrequently due to the superior effectiveness and safety profile of anti-VEGF injections.