Age-related macular degeneration (AMD) is a common eye condition that can lead to significant vision impairment, particularly for individuals over 50. While there are two main forms, the “wet” type is less common but often results in more severe and rapid vision loss. Understanding this condition and its treatments is important for preserving eyesight.
Understanding Wet Age-Related Macular Degeneration
Wet age-related macular degeneration (wet AMD) is an advanced form of AMD characterized by the abnormal growth of new blood vessels beneath the macula. The macula is a small, specialized part of the retina at the back of the eye, responsible for sharp, detailed central vision needed for tasks like reading, driving, and recognizing faces. These new blood vessels, known as choroidal neovascularization (CNV), grow abnormally and can leak fluid or blood, causing the macula to swell and scar.
This leakage and scarring directly interfere with the macula’s ability to process light, leading to a sudden and often rapid decline in central vision. Common symptoms include visual distortions, such as straight lines appearing bent or wavy, blurred central vision, difficulty recognizing faces, and a blurry or blind spot in the center of the visual field. While wet AMD does not cause total blindness, as side vision is unaffected, the loss of central vision can severely impact daily activities. Age is a primary risk factor, with most cases occurring in individuals 55 or older.
VEGF’s Role in Vision Loss
Vascular Endothelial Growth Factor (VEGF) is a signaling protein produced by cells throughout the body, playing a role in the formation of new blood vessels, a process called angiogenesis. It is also involved in restoring oxygen supply to tissues when blood circulation is insufficient, such as during wound healing or muscle repair.
In wet AMD, an overproduction of VEGF in the eye leads to detrimental effects. Elevated VEGF levels promote the abnormal growth of fragile new blood vessels under the macula, which are prone to leaking fluid and blood. This leakage causes swelling, hemorrhage, and scar tissue formation, directly damaging the macula and leading to vision loss. The concentration of VEGF in the aqueous humor is significantly higher in patients with wet AMD, highlighting its direct link to the disease’s progression.
Anti-VEGF Therapy for Wet AMD
Anti-VEGF therapy is the primary treatment for wet AMD, designed to counteract excessive VEGF in the eye. This therapy works by introducing medications that bind to and inhibit VEGF activity, blocking its ability to stimulate abnormal blood vessel growth and reduce leakage. By targeting this protein, anti-VEGF drugs can help stabilize vision loss and, in some cases, even improve sight.
Common anti-VEGF medications include ranibizumab (Lucentis), aflibercept (Eylea), faricimab (Vabysmo), and bevacizumab (Avastin). While bevacizumab was initially developed for cancer treatment, it is frequently used off-label for wet AMD due to its effectiveness and cost-efficiency. These medications are administered directly into the eye to ensure the drug reaches the affected area and minimize systemic side effects.
What to Expect from Anti-VEGF Treatment
Anti-VEGF treatment for wet AMD involves a series of intravitreal injections, meaning the medication is delivered directly into the vitreous cavity, the gel-filled space in the eye. Before the injection, the eye is numbed with anesthetic drops, and antiseptic drops are applied to prevent infection. The injection itself is a quick procedure performed in the ophthalmologist’s office.
Patients commonly receive initial injections monthly, with frequency adjusted over time based on their response to treatment. Following the injection, some mild and temporary side effects may occur, such as a sensation of grittiness, eye pain or redness, or seeing floaters. More serious, though rare, complications can include infection (endophthalmitis) or retinal detachment, with the risk of infection being approximately 1 in 2500 injections.