Macular telangiectasia (sometimes called idiopathic juxtafoveal telangiectasis or MacTel) is a disease that affects the macula. That's the part of your eye that allows you to see things directly in front of you.
When you have it, tiny blood vessels around your fovea (the center of your macula) become swollen and enlarged. This leads to a loss of sharp central vision. You need central vision to do important tasks like reading, writing, driving, and seeing other people’s faces.
The most common form of macular telangiectasia was first identified in 1977. Experts estimate about 2 million people worldwide have it.
Though it rarely leads to blindness, macular telangiectasia can be difficult to treat. Research is underway to better understand it, find its causes, and uncover new treatments.
What Are the Symptoms of Macular Telangiectasia?
Early on, people with the condition may not notice any issues. But as the disease advances, symptoms may include:
- Loss of central vision
- Blurry vision
- Distorted vision
- Trouble seeing well in low-light conditions
Macular telangiectasia doesn't affect your side vision.
It's sometimes confused with another, more common condition called macular degeneration. Though they can cause similar symptoms, macular telangiectasia is not the same as macular degeneration.
Types of Macular Telangiectasia
"Telangiectasia" refers to the dilation, or widening, of small blood vessels. The various forms of macular telangiectasia affect the blood vessels in your eyes in different ways. The two main types are:
- Type 1: With type 1, blood vessels in the eye enlarge and bulge, which damages the macula. This type usually involves just one eye. It's believed to be a form of Coats disease, a rare eye disorder that most often affects young men.
- Type 2: This is by far the most common form. With this type, blood vessels enlarge and leak, causing the macula to swell. In some cases, new blood vessels develop within the macula and break or leak. Over time, scarring of the macula can affect your vision. Type 2 usually occurs in both eyes, but each eye may be affected differently. It’s most often diagnosed in people in their 40s and 50s.
There’s also a macular telangiectasia type 3, but it's extremely uncommon and not well understood. It can lead to blocked blood vessels in your eyes.
What Causes Macular Telangiectasia?
Scientists don’t know exactly what causes the condition, but research has provided possible explanations.
Some studies suggest it may occur because of a poor connection between certain types of cells in your retina, the thin layer of light-sensing tissue in the back of your eye that houses the macula.
Researchers have found more than a dozen gene variants linked to MacTel type 2, suggesting a strong genetic link.
What Are the Risk Factors for Macular Telangiectasia?
Here are some risk factors to be aware of:
- Age: MacTel most commonly develops in middle-aged and older people.
- Hypertension, diabetes, or heart disease: If you have these conditions, you could be at higher risk.
- Family history: The disease is thought to run in families.
How Is Macular Telangiectasia Diagnosed?
- Small crystals in the middle of your macula
- Discoloration of the macula
- Abnormal blood vessels of the macula
- Fat deposits
- Clumps of pigment
If your doctor suspects you have macular telangiectasia, these tests may help confirm a diagnosis:
- Optical coherence tomography (OCT): OCT uses light to create images of your retina. It can help doctors identify abnormal blood vessels and swelling.
- Fluorescein angiography (FA): With FA, doctors inject dye into a vein in your arm. Images are taken as the dye travels through the blood vessels in the retina. This test allows doctors to see abnormal areas.
What Are the Treatments for Macular Telangiectasia?
Researchers haven’t yet discovered a therapy that can significantly improve vision in people with macular telangiectasia. Often, the condition isn't serious enough to require treatment. Your doctor will simply monitor you.
In some cases, doctors will recommend:
- Laser treatments: Lasers sometimes help seal leaky vessels.
- Steroid shots: These may help decrease swelling.
- Vascular endothelial growth factor inhibitor (anti-VEGF) shots: Anti-VEGF drugs target a substance in the eye that causes abnormal blood vessels to grow.
How to Manage Low Vision
Certain resources, aids, and devices can help people with vision loss better manage daily activities.
Low vision rehabilitation therapy teaches people ways to stay independent and live better with vision loss. A vision rehab program might also provide counseling, education, and support.
Some examples of low vision devices and aids include:
- Magnifiers: Standup or handheld magnifiers can enlarge objects. Some also provide light.
- Magnifying spectacles: These glasses may be useful when you need to do a close-up task.
- Telescopes: They can help you see objects far away.
- Tablets, smartphones, and computers: These devices often provide voice command options and can enlarge text. You can also download apps for low vision assistance.
- Audiobooks: They read text aloud to you.
What’s the Outlook?
Macular telangiectasia type 2 usually starts to develop in middle-aged people and gets gradually worse over 10-20 years. Researchers estimate that about half of people with this condition will have eyesight of 20/32 or better.
Type 1 is most often diagnosed around age 40. You can have it for years with no symptoms. Like type 2, it often has a good outlook. And it almost always affects just one eye.
What Is the MacTel Project?
When it comes to macular telangiectasia, there’s still a lot doctors don’t understand. That’s why scientists have launched the MacTel Project – an international research effort that aims to uncover new clues about type 2 macular telangiectasia.
The project intends to promote awareness, provide support, and identify possible causes and effective treatments.