Updated on March 28, 2024.
Geographic atrophy is an advanced form of age-related macular degeneration (AMD), a condition that causes the breakdown of photoreceptors. Photoreceptors are light-sensitive cells in the eye. These cells convert light into nerve signals that are then transmitted to the brain along the optic nerve that connects the eyeball to the brain.
In other words, photoreceptors play a vital role in vision—and the loss of photoreceptors will result in vision loss.
Geographic atrophy affects the macula
Geographic atrophy causes dead areas of photoreceptors in a part of the eye called the macula. It is called geographic atrophy because these dead areas resemble features on a map when examined under magnification.
The macula is a dense layer of photoreceptors located in the back of the eyeball. It is part of the retina, and is responsible for central vision, the ability to clearly see details. Reading, looking at images on a screen, recognizing faces, driving, and measuring ingredients when cooking are a few of the many examples of tasks that require central vision. These are also a few examples of the types of tasks that may become difficult when a person has geographic atrophy—and may become more difficult as geographic atrophy progresses.
Treatment for geographic atrophy
In recent years, the first therapies for geographic atrophy have become available. These therapies are drugs called complement inhibitors and act on a part of the immune system called the complement system. While the exact mechanisms of how geographic atrophy occurs are not fully understood, the condition has been linked to abnormal activity in the complement system. Again, this is not fully understood, but the general idea is that abnormal complement system activity causes inflammation that damages cells in the macula.
As the name implies, complement inhibitors suppress (or inhibit) activity in the complement system. Suppressing activity in the complement system can help slow the progression of geographic atrophy—it cannot reverse or fully stop the dead areas of photoreceptors from growing in size, but it can make them grow more slowly. This can help a person make use of remaining central vision for a longer time.
Injections into the eye
The complement inhibitors used to treat geographic atrophy are given as injections into the eye. A person will need multiple injections of a complement inhibitor—and the number of injections and the schedule of injections are something that should be discussed with a healthcare provider.
While the idea of receiving an injection in the eye is intimidating, the process is not painful. The needle is very thin, a numbing agent is used, and most people report feeling pressure against the eye, but not pain.
Other aspects of treatment
The vision loss caused by an advanced form of AMD can affect many areas of a person’s life. As everyday tasks become difficult, a person may become less independent and experience a lower quality of life. Vision loss also increases a person’s risk for feelings of isolation and mental health disorders, including anxiety and depression.
Counseling, social support, and low vision rehabilitation can all be valuable parts of a treatment plan. These approaches cannot treat geographic atrophy directly, but they can help address the impact that geographic atrophy has on a person’s life.
