Geographic Atrophy (GA) is an advanced form of dry macular degeneration in which large, well-demarcated sections of the retina stop functioning.
In simple terms, Geographic Atrophy (GA), is an advanced form of dry age-related macular degeneration (AMD) that causes cell death (atrophy) in areas of the retina and can lead to irreversible vision loss.
These areas of atrophy have clear borders, as seen in the image above. Each defined area of atrophy is called a lesion. As lesions develop, aspects of visual performance can be diminished, such as reading, driving, and seeing in low light. As the lesions expand, and sometimes overlap, they begin to grow into and affect the fovea, causing blind spots (scotomas) and loss of visual acuity in central vision.
GA can occur late in the progression of “dry” AMD, but can also occur even after “wet” AMD has developed and after the use of anti-VEGF injections to stop “wet” AMD. Patients with GA can also develop “wet” AMD.
Why is it called “Geographic Atrophy”?
In images of the retina, areas of dead cells (atrophy) resemble a map, hence the term “Geographic Atrophy.”
Symptoms of Geographic Atrophy
Many of the symptoms documented for Geographic Atrophy are the same, or overlap with Dry AMD, so symptoms alone are not the best indicator of Geographic Atrophy, but can include:
- Difficulty adapting to low light levels
- Need for brighter light
- Images appear with decreased intensity of brightness
- Reduced central vision
- Blurriness of printed words
- Visual distortions
- Difficulty in recognizing faces
Prevalence of Geographic Atrophy
- GA accounts for 20% of all legal blindness attributed to AMD
- Affects approximately 1 million people in the United States
- Affects approximately 5 million people worldwide
- Starting at age 50, prevalence quadruples every 10 years, from 0.16% at age 60, to 2.91% at age 80
What are the Chances that Dry AMD will Develop into Geographic Atrophy?
30% of Dry AMD patients will progress to geographic atrophy.
Risk of developing GA increases as dry AMD advances from early to intermediate, with age, and there is some evidence that risk of GA also increases with certain risk factors such as:
- Smoking or a history of smoking
- Lens opacities
- Previous cataract surgery
One of the strongest risk factors is poor visual acuity at baseline. A study found that patients with visual acuity at or worse than 20/200 had almost a 3-fold greater risk of developing GA than those with a baseline of 20/25-20/40.1
Additionally, several chronic conditions are associated with increased risk of AMD progression. Managing any chronic medical condition should be part of your overall AMD management to reduce the risk or rate of progression of AMD and the potential development of geographic atrophy.
- Cardiovascular disease
- High cholesterol
What are the Chances that a Wet AMD patient will also Develop Geographic Atrophy?
Up to 37% of wet AMD patients can develop geographic atrophy within 2 years. That risk increases over time, so by 7.3 years, 98% of patients with wet AMD also developed geographic atrophy.
Who Should be Examined for Geographic Atrophy?
If you have a family history of AMD, you should work with an eye care specialist to establish a routine of thorough eye exams. At 40, it is recommended that everyone have a complete, dilated pupil eye exam to establish a baseline for eye health.
While currently there are no medically established guidelines for the frequency of eye exams between the ages 40-60, if there is a history of AMD in your family, the American Macular Degeneration Foundation suggests regular exams during that time frame. Early detection can lead to early intervention, a slowing of disease progression, and the preservation of useful sight.
Between 60-65, you should have a dilated pupil eye exam at least once a year, and possibly every 6 months.
If you have been diagnosed with dry AMD, you should have a dilated pupil eye exam at least once a year, every 6 months, or more often if suggested by your retina specialist..
If you have a family history of AMD, the following risk factors may contribute to the development or progression of GA:
- Smoking or history of smoking
- Cardiovascular disease
- Poor diet
- High Cholesterol
- Long-term use of calcium-channel blockers (see: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9296271/)
How is Geographic Atrophy Diagnosed?
Geographic atrophy is a clinical diagnosis, meaning the diagnosis is made by your eye doctor based on your symptoms and what they can see using diagnostic imaging.
- Fundus autoflorescence – currently the standard imaging technology to visualize the retinal pigmented epithelium (RPE) in GA. [links to sub-page with full definition]
- Optical coherence tomography (OCT) – [link to sub-page with full definition]
- Multifocal electroretinography [link to sub-page with full definition]
The Importance of Early Diagnosis
Geographic atrophy lesions outside the fovea grow more quickly than those in the fovea. So, now that there is a treatment available for GA, dry AMD patients should have a discussion with their general ophthalmologist or retina specialist about where they are in the progression of their condition. If dry AMD advances to geographic atrophy, early intervention may help to preserve useful sight.
Geographic Atrophy Treatment
As of 2023, two new medications were approved by the FDA for the treatment of Geographic Atrophy: Syfovre, and Izervay.
Syfovre™ is administered by injection into the eye, and works by targeting a protein in the complement pathway.
In clinical trials, Syfovre™ was shown to reduce the rate of geographic atrophy lesion growth by up to 36% with monthly injection.
Dosing is set at about every 25 to 60 days, according to Apellis, the drug’s manufacturer, depending on the individual’s response.
Syfovre™ is currently not a treatment for early AMD, and does not completely halt disease progression like anti-VEGFs do for wet AMD.
Syfovre™ continues to improve in its ability to slow the growth of sight-stealing lesions and is most effective at 18-24 months.
Syfovre™, and other GA treatments that may follow it, represent a new frontier in macular degeneration treatment. As with other treatments for eye conditions, there are slight risks in using Syfovre™, and patients should speak with their doctors about those risks, which include:
- A slightly elevated risk for developing wet AMD
- Other rare inflammatory eye complications that accompany an injection into the eye (rare cases of occlusive retinal vasculitis have been reported in .01% or 1 in 10,000 injections)
Since patients can have either dry AMD or wet AMD — or both — in either or both eyes, and because Syfovre™ cannot be administered at the same time as anti-VEGFs, new treatment regimens will have to be worked out between retina specialists and patients.
Also see the SYFOVRE safety information page.
Izervay announced FDA approval in August of 2023, becoming the second available treatment option for GA. It works differently than Syfrovre, by targeting excessive activation of the complement system(2) — the immune system’s early response system. Izervay works by blocking excess production of the C5 protein, which researchers believe cause the development of GA lesions and scarring that cause vision loss.
Clinical trials of Izervay showed a reduction in the rate of GA lesion growth by about 35%.
Izervay is given as an eye injection once a month, for up to 12 months.
- Nielsen, M. K., Shah, Y. S., Do, D. V., Bhagat, N., & Lim, J. (2021, December 18). Geographic atrophy. EyeWiki. Retrieved February 20, 2023, from https://eyewiki.aao.org/Geographic_Atrophy
- U.S. Department of Health and Human Services. (2023, December 12). Story of discovery: Nei-funded research paves way for New Dry Amd Drugs. National Eye Institute. https://www.nei.nih.gov/about/news-and-events/news/story-discovery-nei-funded-research-paves-way-new-dry-amd-drugs