Geographic atrophy (GA) is an advanced form of dry age-related macular degeneration (AMD) that leads to progressive and irreversible vision loss. It involves the gradual deterioration of cells in the retina, particularly in the macula, which is responsible for sharp, central vision. Recent scientific advancements have introduced new injection treatments, offering a way to manage this condition and potentially slow its progression. These treatments mark a notable step forward in addressing a previously untreatable cause of vision impairment.
What Geographic Atrophy Means for Your Vision
Geographic atrophy involves the irreversible loss of cells within the retina, specifically impacting the macula. This cellular loss leads to the formation of distinct, well-demarcated areas of atrophy, often referred to as lesions. As these lesions expand over time, they can merge and grow into the fovea, the very center of the macula, causing blind spots (scotomas) and a decline in central visual acuity.
The progression of GA can significantly affect daily activities that rely on sharp central vision, such as reading, driving, and recognizing faces. Individuals with GA may also experience difficulty adapting to low light, a need for brighter illumination, or decreased brightness in images. While the vision loss from GA is typically gradual, it can profoundly impact independence and quality of life. Approximately 1 million people in the United States and 5 million worldwide are affected by GA.
How Injections Help Preserve Vision
New injection treatments for geographic atrophy target the complement system, a part of the body’s innate immune response that has been implicated in the development and progression of GA. In GA, an overactive complement system contributes to inflammation and damage to healthy retinal cells. By modulating this system, these treatments aim to reduce the rate of retinal cell loss.
Two medications, pegcetacoplan and avacincaptad pegol, are approved for GA treatment. Pegcetacoplan inhibits complement factor C3, a protein central to the complement cascade. By binding to C3 and its activation fragment C3b, pegcetacoplan regulates the overactive immune response and reduces inflammatory components.
Avacincaptad pegol targets complement factor C5, further downstream in the complement cascade. By inhibiting C5, this medication prevents its cleavage into C5a and C5b, decreasing the formation of the membrane attack complex (MAC), which contributes to cell damage in GA. Both therapies slow the growth of GA lesions in clinical trials, with the protective effect potentially increasing over time. It is important to understand that these injections are designed to slow the rate of vision loss rather than to restore vision that has already been lost.
The Treatment Experience and Expectations
Receiving geographic atrophy injections involves a procedure performed in a doctor’s office. Before the injection, the eye is numbed with eye drops to minimize discomfort. The injection is quick, delivered directly into the vitreous, the jelly-like substance that fills the eye. After the procedure, patients might experience temporary side effects such as mild eye discomfort, redness, or small floaters in their vision.
The frequency of injections varies, commonly ranging from monthly to every other month, and treatment is ongoing. Regular follow-up appointments monitor the condition and treatment effectiveness.
While well-tolerated, potential risks are associated with these injections. Rare but serious risks include endophthalmitis (an infection inside the eye), choroidal neovascularization (the growth of new, abnormal blood vessels that can leak fluid), and ischemic optic neuropathy. Choroidal neovascularization can be treated with other injections if it occurs. Patients should discuss all potential benefits and risks with their ophthalmologist to determine if this treatment is appropriate.