Wet age-related macular degeneration (AMD) is a primary cause of severe vision impairment in older populations globally. This condition affects the macula, the central part of the retina responsible for sharp, detailed central vision. The introduction of intravitreal injections, specifically Anti-Vascular Endothelial Growth Factor (Anti-VEGF) therapy, has fundamentally changed the prognosis for individuals diagnosed with Wet AMD. These treatments are now the standard of care, offering a powerful method to manage the disease. This article explores the effectiveness of these injections, detailing the metrics of success, the variables that affect long-term outcomes, and the practical realities of the treatment schedule.
Understanding Wet Macular Degeneration and Anti-VEGF Therapy
Wet AMD is characterized by choroidal neovascularization, the growth of abnormal, fragile blood vessels beneath the macula. These new vessels often leak fluid and blood into the retinal layers, leading to swelling, scarring, and rapid loss of central vision. This growth and leakage is triggered by an excess of Vascular Endothelial Growth Factor (VEGF), a specific signaling protein.
Anti-VEGF therapy involves injecting medications directly into the vitreous gel of the eye to counteract this protein. Common drugs include ranibizumab (Lucentis), aflibercept (Eylea), and bevacizumab (Avastin), which work by binding to and blocking the VEGF protein. By inhibiting this growth factor, the treatment stops the abnormal vessels from growing and reduces fluid leakage, stabilizing the macula and preserving existing vision. Newer agents, such as brolucizumab (Beovu) and faricimab (Vabysmo), sometimes offer a longer duration of action between doses.
Defining Treatment Success and Typical Outcomes
Success is measured across two primary categories: stabilization and improvement of vision. Stabilization, or preventing further vision loss, is the most frequent goal of therapy. Clinical data consistently show that up to 90% of patients maintain their visual acuity or lose fewer than 15 letters on a standard eye chart over a one-to-two-year period.
The second metric is improvement in visual acuity, meaning gaining letters on the eye chart. In large-scale studies, 30% to 40% of patients experience a measurable gain in vision, sometimes recovering function enough to improve their ability to read or drive. Early trial data reported an average gain of about 9 letters after the first year of consistent treatment, which is generally sustained for several years with continuous therapy.
Functional success is tied to a patient’s daily quality of life. Even small gains or the cessation of deterioration significantly impact independence, such as the ability to recognize faces or read large print. While long-term real-world outcomes show average visual gains decline modestly over many years, this result is vastly superior to the severe vision loss guaranteed before Anti-VEGF therapy.
Patient-Specific Factors Influencing Long-Term Visual Results
Individual outcomes vary widely despite encouraging overall statistics. The timing of the initial diagnosis and treatment is the most significant factor influencing long-term visual prognosis. Eyes that begin therapy when abnormal vessels are small or vision loss is minimal have a greater potential for recovery. Delaying treatment allows leaky vessels to cause irreversible damage and scarring to the macula’s delicate photoreceptors.
Lesion Characteristics and Health
The characteristics of the lesion, including its size, location, and subtype of choroidal neovascularization, also affect the response to therapy. Patients with certain subtypes may respond differently, sometimes requiring a switch in the specific Anti-VEGF agent to achieve optimal fluid control. A patient’s overall health can also influence the eye’s response; for example, coexisting systemic conditions like diabetes correlate with a less satisfactory visual outcome.
Adherence to Treatment
Adherence to the prescribed treatment and monitoring schedule is paramount for maintaining long-term success. Studies show that a higher number of injections administered in the first year correlates with better visual outcomes, emphasizing the need for consistent suppression of disease activity. Non-compliance, often driven by the burden of frequent visits, is a primary reason why real-world results fall short of clinical trial averages. Selecting a drug that allows for longer intervals between injections, once the condition is stable, can improve adherence.
The Treatment Process and Monitoring Frequency
The Anti-VEGF treatment process typically begins with a “loading phase,” involving a series of initial injections administered frequently, often monthly, for the first three or four months. The goal of this intensive phase is to rapidly dry out the macula by suppressing the VEGF protein and halting fluid leakage. This aggressive initial approach establishes control over the disease activity.
Following the loading phase, the clinician transitions the patient to an ongoing, individualized maintenance regimen. The most common approach is the “Treat-and-Extend” regimen, where the interval between injections is gradually lengthened by one or two weeks as long as the macula remains stable. This allows the doctor to find the longest possible period between treatments while maintaining disease control.
Monitoring is integral to the maintenance phase and relies heavily on high-resolution imaging, specifically Optical Coherence Tomography (OCT) scans. OCT provides a cross-sectional view of the retina, allowing the physician to precisely measure fluid within and beneath the macula. If the OCT scan shows a recurrence of fluid or swelling, the injection interval is shortened; if the macula remains stable, the interval is extended.