What Is Geographic Atrophy?

People with geographic atrophy (GA) of the eye's light-sensitive retina experience the progressive loss of retinal pigment epithelium (RPE). The RPE is a layer of cells between the retina's photoreceptor cells and the layer of blood vessels underneath that nourishes the retina.

Geographic atrophy is a chronic progressive condition that tends to occur in the late stage of age-related macular degeneration (AMD). In this condition, the pigmented retinal cells die, resulting in patches that look different from the rest. The name of the condition comes from this appearance, which is like distinct regions on a map.

Geographic atrophy affects about 20% of people with AMD. Around the world, approximately 8 million people have the condition in at least one eye.

This article will cover the symptoms of geographic atrophy, its potential causes, how it's diagnosed, and what to expect if you have geographic atrophy.

Symptoms

In the beginning, geographic atrophy may have no symptoms. The symptoms can take a long time to appear. As the disease progresses and more cells are lost, you may begin to experience the following symptoms:

• Missing some letters while reading or finding that small portions of a person's face cannot be seen
• Needing extra light for reading
• Having trouble doing things in the dark
• Colors appear muted
• Having trouble seeing when doing tasks that require detailed vision (e.g., driving, cooking, sewing, or telling different faces apart)

Causes

The exact cause of geographic atrophy is not clear, but researchers continue to find factors that appear to play a role in a person's risk, such as:

• Genetics
• Environment
• Immune system dysfunction
• Low-grade inflammation in the eye affecting the retina
• The thickness of the choroid (the vascular layer of the eye that contains retinal pigmented epithelial cells) when just one eye is involved
• Müller cells (a type of cell that helps to support the retina), which may play a role when both eyes are affected

Diagnosis

To be diagnosed with geographic atrophy, you'll need to be seen by a healthcare provider that specializes in eye health (ophthalmologist).

During an office visit, they will widen (dilate) the pupil (the opening in the center of the iris) to look inside the eye. When they do this, they can see that an area of the retina is missing its dark pigment.

You may also have retinal imaging during the exam. Some imaging techniques that the ophthalmologist may use are:

• Color photographs of the retina (fundus photographs) can show protein deposits (drusen) on the tissue and can be compared to see how the retina changes over time.
• Autofluorescence photographs allow a provider to view the layers of the retina with the help of fluorescent blue light. The dye is injected (usually in a vein in the arm) and circulates to the eye, where it can light up problem areas.
• Optical coherence tomography (OCT) gives a cross-sectional view of the back of the eye. OCT can show any fluid under the retina or if the tissue at the center (macula) is thickening.
  

Treatment

There is currently no effective treatment for slowing geographic atrophy or reversing the effects of the condition.

However, if the geographic atrophy is somewhat off-center and has not compromised the detailed vision associated with the fovea (the region of the eye with the highest quality vision), your provider may recommend visual rehabilitation.

This kind of rehabilitation can help manage any decrease in contrast sensitivity that may affect your overall vision or reading ability.

Prognosis

Geographic atrophy is a progressive condition that tends to affect the center part of the visual field, where you have your most detailed vision. With time, it can cause more and more vision loss in this area while leaving the side vision intact.

There is currently no treatment for geographic atrophy. As it progresses, a person with the condition will experience more significant vision loss that is permanent.

The growth rate for geographic atrophy areas is, on average, around 2.1 square millimeters per year—but each person with the condition progresses at their own rate.

Coping

It's not yet possible to treat geographic atrophy, but there are strategies that can help you maximize your remaining vision. If you experience a significant number of blank spots in your central vision, your ophthalmologist can refer you to a low-vision specialist for help. They can recommend ways to optimize your remaining vision.

Some strategies for coping with vision loss from geographic atrophy include:

• Using a magnifying device to increase the size of letters for reading
• Getting large-print books, newspapers, and other materials
• Increasing the size of a printed page and using a closed-circuit television to put it on a screen
• Using telescopes for watching television, seeing street signs or billboards, or finding house numbers
• Increasing the amount of light in your surroundings
• Getting an implantable miniature telescope in one eye to make use of the intact light-sensitive retina portions and improve your reading ability
• Use computers, tablets, or special software to enhance your reading

Summary

With geographic atrophy, retinal pigment epithelial cells (usually at the center of the vision) begin to die. About 20% of people with late AMD are affected by geographic atrophy. The symptoms of the condition can range from missing letters while reading to difficulty distinguishing faces or doing activities requiring detailed vision.

The vision loss from geographic atrophy is permanent, and there is currently no treatment to slow or reverse the process. However, there are vision aids that can help optimize your remaining vision if you are diagnosed with the condition.

A Word From Verywell

Learning that you have geographic atrophy is difficult, but remember that the condition does not progress quickly. Researchers are also working on ways to treat the condition. Although there is currently no way to stop the condition from progressing, strategies are available to help maximize your vision and help you continue participating in many visual activities.