Geographic atrophy (GA) is an advanced form of dry age-related macular degeneration (AMD). It involves the gradual loss of retinal cells, leading to irreversible damage and blind spots in central vision. GA is a major cause of permanent vision loss among older adults globally, affecting an estimated 8 million people worldwide. This condition progressively impairs the sharp, detailed vision needed for daily activities.
How Geographic Atrophy Affects Vision
Geographic atrophy targets the macula, the retina’s central region responsible for sharp vision. As macula cells deteriorate, individuals experience blurred central vision, making tasks like reading or recognizing faces challenging. This damage can also lead to distorted vision, where straight lines appear wavy, a symptom known as metamorphopsia.
Over time, the death of these light-sensing cells creates blind spots, or scotomas, in the central visual field. These blind spots can enlarge, significantly impacting daily activities like driving or engaging in hobbies requiring fine detail. While peripheral vision remains unaffected, the progressive loss of central vision impacts a person’s independence and quality of life.
Causes and Risk Factors for Geographic Atrophy
Geographic atrophy is a complex condition influenced by multiple factors. Age is the most significant non-modifiable risk, with the risk of developing GA increasing considerably for individuals over 60. Genetic predispositions also play a substantial role, as a family history of AMD increases susceptibility.
Beyond age and genetics, several environmental and lifestyle factors contribute to GA risk. Smoking significantly elevates risk, and a diet lacking in antioxidants, particularly from dark green leafy vegetables, is implicated. Other health conditions like cardiovascular disease, high blood pressure, high cholesterol, diabetes, and obesity are associated with increased GA development. Prolonged UV light exposure may also contribute to retinal cell damage, increasing susceptibility.
Diagnosing and Monitoring Geographic Atrophy
Ophthalmologists use several methods to diagnose geographic atrophy and track its progression. A comprehensive eye examination is a key step, including visual acuity tests and a dilated fundus exam to view the retina. During this exam, the doctor looks for characteristic signs like drusen (yellow deposits) and retinal pigment epithelium (RPE) atrophy.
Optical Coherence Tomography (OCT) is a non-invasive imaging technique providing high-resolution cross-sectional views of retinal layers for precise measurement of atrophy and subtle changes. Fundus autofluorescence (FAF) is another specialized imaging tool that maps RPE cell loss, appearing as dark patches, showing atrophic lesions. Regular monitoring with these advanced imaging techniques is important for assessing disease progression and guiding management strategies.
Managing Geographic Atrophy
Currently, there is no cure to reverse vision loss from geographic atrophy, but treatments are available to slow its progression. Two medications, pegcetacoplan (SYFOVRE) and avacincaptad pegol (IZERVAY), are approved for GA treatment. These therapies target components of the complement system, part of the immune system implicated in the disease, slowing the growth of atrophic lesions. They are administered as injections into the eye, typically monthly or every other month.
While these treatments are a major advance, lifestyle modifications also help. Quitting smoking is important, as is maintaining a healthy diet rich in antioxidants. For individuals at risk of advanced AMD, Age-Related Eye Disease Study 2 (AREDS2) supplements, containing specific vitamins and minerals, can help slow dry AMD progression and may slow GA lesion expansion towards the central macula. Low vision aids like magnifiers and electronic devices, along with vision rehabilitation, are important for helping individuals maximize remaining vision and maintain independence. Ongoing research and clinical trials continue to explore new treatments.