Myopic macular degeneration (MMD) is a serious eye condition that can cause vision loss.

Known also as “pathological myopia” and “degenerative myopia,” it most commonly develops in people who are very nearsighted.

People who are nearsighted can see objects that are close but may have trouble seeing objects farther away. It’s sometimes referred to as shortsightedness.

MMD isn’t the same as just being nearsighted and not being able to see faraway objects clearly, which is known as myopia.

Instead, MMD means there are degenerative changes happening in your eye, and these changes may not be treated with just glasses or contact lenses. In fact, it can lead to legal blindness if left untreated.

Read on to learn more about MMD, the other vision issues it can present, and how to manage and treat this eye condition.

MMD occurs when your retina in the back of the eye slowly stretches out over time. This causes the eyeball to evolve from a circular ball shape into more of a football shape. The retina becomes thinner as it stretches, and as that happens, the part of the eye that allows you to see sharp details in the center of your vision (the macula) also stretches and becomes damaged.

This leads to blurry and distorted vision in the central part of your vision, making it more likely you could develop a retinal tear or more serious problems in the eye.

People with myopia experience an elongated eyeball, which can damage the retina and macula and cause distorted vision.Share on Pinterest
Illustration by Sophia Smith

While myopia itself is fairly common, MMD is less common, as it affects about 3 percent of people worldwide.

Researchers believe that MMD is caused by a combination of genetic and environmental factors, though more studies are needed to determine the specific root causes.

Still, there are some known risk factors for this condition:

  • High grade myopia. Any prescription strength higher than -6.0 is considered high grade, and people with a prescription strength over -10.0 are at an even higher risk.
  • Family. Both high grade myopia and MMD often run in families, and pathological myopia may sometimes be diagnosed in children.
  • Ethnicity. MMD is more commonly seen in Asia. An older 2009 research article indicates Chinese Americans are at a higher risk of developing the condition, and people with Japanese ancestry also have an increased risk.

You might not notice any symptoms of MMD at first.

The condition progresses slowly, and you may not initially notice any symptoms. When symptoms do occur, they may include:

  • distorted vision
  • wavy lines in your vision
  • gradually worsening vision
  • blank spots in your vision
  • trouble adjusting to light
  • difficulty seeing shades of color
  • trouble seeing in dim light

Because the condition generally occurs in people who already have high grade myopia, some symptoms might be hard to distinguish from everyday visual difficulties.

It’s important to visit an eye doctor at least once a year for an eye exam and reach out to a doctor about any concerns you may have about your vision.

While this condition is similar to age-related macular degeneration (AMD) in some ways, they are not the same.

The two conditions share many of the same symptoms and can cause vision decline. Both are linked to the gradual wearing down of your eyes’ maculae.

But while AMD is related to age as you get older, MMD is linked to genetics and high grade myopia. It often starts at a much younger age than AMD, which is typically seen in those ages 65 and older.

Myopic macular degeneration can lead to multiple eye complications. Some of these complications are severe and require immediate treatment. Complications can include:

  • Retinal atrophy. When your retina stretches as a result of myopic retinal degeneration, it can cause your retina to become thinner. Over time, this can cause your retina to atrophy, or break down. Retinal atrophy can damage your vision.
  • Detached retina. Retinal stretching can lead to retinal tearing and detachment. Symptoms of retinal detachment include sudden flashes of light in your eyes and seeing dark “floaters” in your vision.
  • Lacquer cracks. Stretching can cause breaks in your macula and in a layer of your eye called Bruch’s membrane. These cracks are called lacquer cracks.
  • Choroidal neovascularization. Lacquer cracks and retinal atrophy leave open areas in your eye. Sometimes, thin and fragile new blood vessels grow into these spaces. This is known as choroidal neovascularization (CNV), and it can lead to scarring and vision loss. As many as 10 percent of people with MMD develop this CNV complication, and it’s one of the leading causes of blindness in the United States for those 50 years and older.

An annual vision exam can help you detect and treat any complications before they become emergencies.

There is no cure for this eye condition, but for those not experiencing any vision loss symptoms, you may be able to wear glasses or contact lenses to address nearsightedness. Either option can make it easier to see by refocusing the way that light hits your retina.

You might also need treatment for some MMD complications, and that might include:

MMD generally can’t be treated with laser vision surgery.

It’s important to have regular eye appointments if you have macular myopic degeneration. It’s also best to let your eye care team know about any changes to your vision as soon as possible.

Myopic macular degeneration is a severe form of myopia, or nearsightedness, that gets worse over time.

It can lead to legal blindness and severe complications, such as retinal detachment and choroidal neovascularization.

There is no cure for MMD, but many people can use glasses and contacts to help their vision, even though this doesn’t address the underlying condition. Additionally, some complications of the condition can be treated if they are caught early.

It’s very important to have regular eye appointments, especially if you have high grade myopia or myopic macular degeneration. Having regular appointments can help your doctor catch and treat any complications or eye health issues before they become severe.