Fuchs' dystrophy (fooks DIS-tre-fe) is a rare disorder that affects the cornea — the transparent front surface of your eye. Although the cause of Fuchs' dystrophy is unknown, it often occurs as an inherited disorder. Normally, the cells that line the back surface (endothelium) of the cornea prevent excess fluid from accumulating in the cornea. This helps the cornea maintain its transparency. But with Fuchs' dystrophy, those endothelial cells slowly deteriorate and die off. As a result, fluid builds up in the cornea. This may cause swelling, cloudy vision, pain and loss of corneal transparency. Fuchs' dystrophy causes a variety of vision problems and can eventually lead to blindness. Fuchs' dystrophy is considered one type of corneal dystrophy.

Alternative Names of Corneal Dystrophies are: Fuchs' dystrophy.

Causes of Corneal Dystrophies

In some people with Fuchs' dystrophy, the cause is unknown. However, for many people it's inherited as an autosomal dominant familial condition, meaning that about half of an affected person's children also will have the disease. The extent to which relatives experience signs and symptoms may vary. For instance, a parent with a mild case and few symptoms could have a child with a severe case and numerous vision problems.

Signs & Symptoms of Corneal Dystrophies

Doctors may see early signs of Fuchs' dystrophy in people who are in their 30s and 40s. But most people don't experience symptoms or problems until they're in their 50s and 60s. Signs and symptoms usually affect both eyes and include:

• Blurred vision on awakening that may gradually clear up as the day goes on
• Painful, tiny blisters (epithelial blisters) on the surface of your cornea — caused by excess fluid within the cornea
• Visual impairment, distorted vision and changes in vision
• Difficulty seeing at night
• Blindness
• Sensitivity to light
• Seeing halos around lights (astigmatism)
• A cornea that is cloudy or hazy in appearance

Diagnosis of Corneal Dystrophies

You may go through testing so that your doctor can determine whether you have Fuchs' dystrophy. Testing may include:

• Visual acuity. This is a basic standard test that is used during routine eye exams. You'll be asked to look at a chart with letters and numbers on it and read the characters. This test helps determine if your vision has worsened since your last exam.
• Glare test. Similar to the vision acuity test, a bright light is directed at your eye while you read the characters on the chart. This test helps to determine if bright light reduces your ability to see. For example, if you notice you have a hard time seeing when you drive toward headlights at night, you'll probably have decreased visual acuity during the glare test.
• Grade or guttata stage. Your doctor uses an optical microscope called a slit lamp to look inside your eye. Your doctor then examines the endothelial cells in your cornea. If there are irregularities, called guttae, on the back surface of the cornea that is a sign of Fuchs' dystrophy. After this exam, your Fuchs' dystrophy may be assigned a "grade" or "stage" of zero through five. This number indicates the severity of dystrophy. A zero means there's no disease while a five means much of your cornea is affected.
• Corneal cell count. Your doctor may use a special instrument that records the size and shape of your endothelial cells. The instrument also measures the number of endothelial cells within a specific part of your cornea. A lower cell count usually correlates with advanced disease. This test is used to diagnose Fuchs' dystrophy and other conditions.
• Corneal pressure test. Your doctor may numb your eyes with drops. Then your doctor will momentarily touch your eye with a special instrument that measures pressure within the eye.
• Corneal thickness test. For this test, your doctor uses ultrasound to determine the thickness of your cornea. If your cornea is too thick, it could be the result of excess fluid that has caused the cornea to swell. This swelling is usually seen in people with moderately advanced Fuchs' dystrophy.

Treatments of Corneal Dystrophies

Your doctor may suggest the following methods and procedures to improve your comfort or stop your symptoms and signs of Fuchs' dystrophy from worsening.

• Use eye drops or ointments to reduce the amount of fluid in your cornea.
• Use a hair dryer and hold it at arm's length. Direct warm — not hot — air across your face two or three times a day to evaporate excess fluid in the cornea and dry out blisters.
• Wear soft contact lenses to improve vision and reduce discomfort.
• Receive a corneal transplant, also known as keratoplasty, which replaces damaged cornea tissue with healthy tissue from a donor. There are many types of corneal procedures — some replace only a few thin layers of the cornea, while others replace the entire cornea. For Fuchs' dystrophy, an increasingly common procedure replaces only the deep layers of the cornea, including the endothelium. This is sometimes referred to as endothelial keratoplasty or posterior lamellar keratoplasty. Corneal transplants are common and have high success rates. However, you may have to wait a long time for donor tissue to become available. And some people develop problems following transplants. About 20 percent of the time, the transplant recipient's body attempts to reject the new corneal tissue, according to the National Eye Institute. The rejection may cause increased sensitivity, redness, pain and worsening vision. Many times, rejection can be managed with topical eye medications. After corneal transplant, your eyes may feel uncomfortable. You'll need to use eye drops for several months to help your eyes heal. The majority of people who have a successful transplant for Fuchs' dystrophy continue to be free of symptoms for at least ten years.
• Participate in research or a clinical trial. Clinical trials involve studies of new ways to diagnose or treat a condition. Clinical trials don't always offer a definite diagnosis or cure, but they may allow you to take advantage of the latest knowledge about your condition. For example, there are studies under way about what genes may be involved in Fuchs' dystrophy.

When to seek Medical Advice

If you experience some of these symptoms, and especially if they get worse over time, see your eye doctor (ophthalmologist or optometrist). If symptoms develop suddenly, call an ophthalmologist for an urgent appointment. Many conditions that cause the same symptoms as Fuchs' dystrophy require prompt treatment.