The retina is the lining that covers the inner wall of the back of your eye. The cells in the retina are sensitive to light. They send signals to your brain so you can see. When you have hereditary retinal dystrophy (IRD), a mutation in your genes changes the way your retina works.
While these disorders are considered rare, there are different types. says Mandeep Singh, MD, PhD, a retina specialist and co-director of the Center for Genetic Eye Disease (GEDi) at the Wilmer I.V. Johns Hopkins Medicine Institute in Baltimore.
Different types of IRDs appear at different ages and cause different types of symptoms. But all IRDs cause symptoms that affect your eyesight.
Some IRDs can cause symptoms elsewhere in your body. These are called syndromic retinal atrophies. Most IRDs are degenerative, which means they get worse over time.
What are some common types of IRDs?
retinitis pigmentosa; This is the most common group of IRD conditions. More than 1 in 3,000 people have it. The genetic mutation that causes retinitis pigmentosa occurs in the rod cells of your eyes.
“The rods are activated when you need to see in low light, like at night or in a dim restaurant or movie theatre,” says Singh. That’s why the most common symptom involves trouble with night vision, he says. In addition, you may lose peripheral (side), central, or color vision.
There are more than 100 genes that can cause retinitis pigmentosa, so doctors don’t use a single treatment for it. If your retina is swollen, you may need medicated drops. Surgery can help treat cataracts that you may have. Specialists can help you with devices and tools that help you work with low vision.
Vitamin A may help with some forms, although you may need genetic testing to confirm you have retinitis pigmentosa before trying this treatment, because it can make other forms of IRD worse.
Stargardt’s disease. Symptoms of Stargardt’s disease usually appear in childhood. This condition affects a specific part of the retina called the macula. The macula is what helps you get sharp central vision. A mutation in a gene called ABCA4 causes fat to build up around the macula, which affects how well you see.
“Normally with Stargardt, you’ll have difficulty reading fine print, facial recognition, and fine vision,” says Singh. You may also have:
- Gray, black, or blurry spots in the center of your vision
- photosensitivity
- Trouble adjusting between light and dark places
- color blind
To diagnose your condition, your doctor may test your color vision, take pictures of your retina to check for yellow spots on your retina, or perform a test called an electroretinogram to see how well your eyes respond to light.
There aren’t any cures for Stargardt’s disease yet, but you can slow vision loss if you take steps like avoiding vitamin A and secondhand smoke.
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conical dystrophy; You develop cone dystrophy when cells called cones in your retina begin to lose their function. Cone cells are found in the macula, and they help you see color and deal with bright light.
In addition to difficulty seeing color, you may also experience eye pain when you are in a lot of light. “People with cone dystrophy tend to turn away and be visually uncomfortable in bright lighting conditions,” Singh says.
You may have symptoms of cone dystrophy when you are born, or you may develop them over time. Cone dystrophy is an X-linked mutation, which means it is passed down through the X sex gene. Men are more likely to have it than women.
There is no cure for cone dystrophy, but you can relieve symptoms by using tinted lenses or dark sunglasses in bright environments. You can also use magnifying devices to help you see fine prints or other detailed items.
Retinal detachment in juveniles. This condition is caused by a genetic mutation that affects the structure of the retina. “Juvenile retinoschisis affects the ability of retinal cells to stick together,” says Singh. “The retina expands and fluid builds up, and that damages vision.”
It only affects males, and symptoms usually appear before the age of 10. Retina splitting means “the retina has split into two layers”. It can cause bleeding in your eye and retinal detachment (pulling away). You may have difficulty reading and recognizing faces, lose your peripheral vision, and have difficulty seeing in general.
Your doctor can diagnose the problem by looking at the back of your eye for tears or tearing. They may also use electroretinography to see how well your retina works with light. If you have bleeding in your eye, your doctor may use ultrasound to check for abnormalities.
You may need surgery if you have frequent eye bleeding or if your retina has detached. You may also need to take certain precautions in your daily life to prevent further damage. “There should be long discussions about potential harm from contact sports,” says Pulido.
Familial exudative vitreoretinopathy (FEVR). FEVR is a retinal vascular disease, which means that it involves the blood vessels of the retina. “FEVR affects the retina’s ability to get enough oxygen, which means it doesn’t get enough nutrients for its function, and you have vision problems,” says Singh.
When you have it, you may have vision loss or blindness, retinal detachment, and eyes that don’t line up in the same direction due to weakness of the eye muscles (strabismus). You may also have whites in the black part of your eye (the pupil). Some people with this condition have no vision problems at all.
Your doctor can treat FEVR with laser therapy. You may also need surgery to reattach your retina if it has pulled too far from the back of your eye.
Congenital Leber’s disease (LCA). A congenital condition is one you had at birth. Babies born with LCA have cone and rod cells that don’t work the way they should. This often causes severe vision loss or blindness.
You may also have crossed eyes, eyes that move quickly and on their own, sensitivity to light, or cloudy lenses (cataracts). Some experts consider LCA to be a severe form of retinitis pigmentosa.
Mutations in more than twenty different genes can cause LCA. Your parents must pass the mutation on to their child for the child to have the condition. As scientists identify the genes responsible for LCA, they are also working to develop gene therapies to help treat specific mutations.
“LCA has made headlines in recent years because the Food and Drug Administration approved a drug for gene therapy for a specific subtype of LCA — LCA2 — caused by a mutation in a specific gene called RPE65,” says Singh.
Treatment can help improve eyesight in people with LCA2. Only 6% of people with LCA have this type.
Genetic testing for IRDs
Although your doctor can diagnose many IRDs using tools such as physical exams and vision tests, a key part of diagnosing and treating your IRD is finding out which mutation you’re dealing with.
“Genetic testing can be a pivotal moment in your clinical journey,” says Singh.
“Once we know the exact gene that causes your condition, we can tell you what we know about it, how it runs through families, and which companies and universities are developing treatments for those genes in clinical trials. It helps you understand more about your disease and make choices regarding your family and their personal health.”
