Geographical atrophy: An expert’s perspective
By Sharon Solomon, MD, as told to Keri Wiginton
Geographic atrophy (GA) is an advanced dry form of age-related macular degeneration (AMD). Up to 20% of people with AMD may get it. Although GA occurs in all populations and races, it is more common in older people with a family history of AMD and people of European descent.
GA usually progresses incredibly slowly, but it can be devastating for the subset of people who get it. However, the FDA recently approved the first drug treatment for GA. And I expect we’ll see more opportunities down the line.
I want people to know that it is rare to go completely blind from this condition. GA does not affect side vision and you can look around, get dressed and take care of yourself in the morning.
Again, I want to reassure people, even those with late-stage disease, that you can maintain your independence with GA. Other eye conditions can make it difficult to tell the difference between night and day. This is not it.
What is geographic atrophy?
People with GA lose light-sensitive cells and tissue in the retina. This thinning or atrophy usually occurs very close to the center of the back of the eye or macula. You can use this area for reading, driving, or focusing directly on any fine detail.
For example, when looking at the word “the,” it uses the central part of the macula, the fovea, to focus on the “h” in the middle. Geographic atrophy often occurs in this area.
People often tell me that they can’t see letters when they try to read a newspaper. As atrophy increases, whole words may disappear. And in severe cases, they can’t read anything on the page because everything they focus on is in this blank area. The missing part of the visual field is called a scotoma.
If you have a loved one with GA, it can be difficult to understand what they are going through. Relatives often tell me that they do not understand why you say that their loved ones have vision problems. They know that their mother sees them because they have seen her pick up a pen, get dressed, or put on makeup.
I will try to explain that the disease does not usually progress far enough to affect tissues outside the macula. Your loved one can navigate the world well with peripheral or side vision that remains intact.
For example, I’ve treated people with GA who can walk into the exam room and sit down—so we know they can see—but when we ask them to read letters on a chart, they ask, “What chart?”
The entire diagram disappears because the empty spot of central vision has become so large.
What are the symptoms of geographic atrophy?
Geographic atrophy affects everyone differently, and some people don’t even realize they have it. In the early stages, you may think you have reading problems because you need a new prescription for your glasses.
But it may have trouble recognizing faces. Some GA people say that when they look directly at people, they can’t see their eyes or nose. But they can use their side vision to see the top of someone’s head and shoulders.
GA can affect how well a person can see contrast and may not be able to tell the difference between colors. This is because your cones (cells that control color) are in the macula. Its black and white cells are in the peripheral retina.
No one has ever told me that they only see in black and white. Someone with GA can probably stand in a pasture and know that the barn is red. But they tell me they are less prepared to pick up color when they read. And they may not be able to tell the difference between blue or green printing, for example.
At some point, GA sufferers may have so many blind spots that it is unsafe to drive.
But when people don’t want to give up their keys, I explain that if you’ve lost some or all of your central vision, you may not notice or react quickly enough to avoid an animal or child running out. the road. It tends to hit people.
People with GA sometimes get Charles Bonnet syndrome. What happens is that people can see fully formed images that aren’t there, but at the same time they don’t have auditory hallucinations. They tend to see things that are familiar to them. Like dreams, these visions can be mundane or creative. But this is usually based on some lived experience.
This visual phenomenon occurs in people with AMD and other vision-loss diseases. I don’t think we know exactly what causes it, but the explanation is that the brain is trying to fill in the missing data.
It is understandable that people who cannot see things are often afraid to speak up. But when they get the courage to tell what is happening, they describe seeing things like pink fences floating or flowers on trees in winter. A dead loved one can appear and disappear.
As I described, these visual hallucinations usually last for seconds or minutes. It’s not like your dead friend or family member is sitting with you all day. And people are extremely accommodating and extremely relaxed when I explain what’s going on and that it’s not a psychological or psychiatric problem.
Still, it’s important to let your doctor know if you see things that aren’t there. If you have a loved one with GA, ask if this happens to them. Other things can cause visual hallucinations, including medication or other health problems.
Advice for carers
Sometimes family members are not as sympathetic and are frustrated because they don’t understand why their loved one with GA struggles to see only certain things.
I will try to explain how GA affects one’s fine focus. So if someone can drop the pen and pick it up because the pen is big and they can see it with their peripheral vision. But those same people may still have trouble reading, driving or paying their bills.
Sometimes a family member comes and looks through the microscope with me like a medical student. I point out the color differences that show where pieces of the retina are missing, but some areas are intact. This can be an eye opener.
Future management of geographic atrophy
In the past, much emphasis has been placed on the treatment of wet AMD. But you can definitely see drug manufacturers and others pouring research dollars into treating GA.
And it is encouraging that this new drug has been approved by the FDA. I haven’t used it yet, and I don’t know of any of my colleagues using it. But it’s good to know that drugs are being developed that target the biological pathways that cause GA to progress.
I tell people that the outlook for GA treatment is promising. Just like when our first therapy came out for wet AMD and 5 years later we got another therapy that blew the old one out of the water, I suspect we’ll see that here.
Things to do after diagnosis of GA
Without a cure, I always consider lifestyle changes that can help preserve the vision someone has lost. And since we know that smoking or exposure to secondhand smoke can increase the chance of GA, I recommend that people stop smoking or spend less time around smokers.
The second thing I will do is make sure that someone with GA is taking the AREDS supplement. These are specific blends of high-dose vitamins and minerals that can slow the progression of moderate dry AMD to late-stage disease.
Unfortunately, GA can lead to vision loss, which makes everyday life difficult. But people amaze me every day with their flexibility and adaptability.
The good news is that I can refer people to low vision services if they need it. Visual aids, such as stronger glasses or magnifiers, can help people read better and function normally for much longer.