Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The disease that we will be learning about today is:

Fuchs Endothelial Corneal Dystrophy

Also known as Fuchs dystrophy.

What is Fuchs Endothelial Corneal Dystrophy?

• Fuchs’ dystrophy (fooks DIS-truh-fee) is an eye disease in which the innermost layer of cells in the cornea undergoes degenerative changes. This cell layer, called the endothelium, is responsible for maintaining the proper amount of fluid in the cornea. The endothelium keeps the cornea clear for good vision by pumping out excess fluid that could cause corneal swelling.​
• Fuchs’ dystrophy can have a genetic cause, but it also can occur without a previous family history of the disease. In many cases, the cause is unknown.​
• There is no known prevention for Fuchs’ dystrophy.​
• Vision problems from Fuchs’ corneal dystrophy usually affect people after age 50, though eye doctors can detect early signs of the disease in younger adults. It appears to be more common among women than men. 

How Do You Get It?

• If your mother or father has Fuchs’ dystrophy, you have roughly a 50 percent chance of getting the disease.​
• The late-onset form of Fuchs endothelial dystrophy is a common condition, affecting approximately 4 percent of people over the age of 40 in the United States. The early-onset variant of Fuchs endothelial dystrophy is rare, although the exact prevalence is unknown.​
• Genes commonly mutated in this disorder include COL8A2, SLC4A11, and ZEB1

What Are The Symptoms?

• Glare and sensitivity to light​
• Eye pain​
• Foggy or blurred vision​
• Seeing colored halos around lights​
• Difficulty seeing at night​
• Poor vision upon awakening that may improve later in the day​
• A feeling that something is in your eye (foreign body sensation)​
• The early clinical signs of Fuchs’ dystrophy are a reduced number of endothelial cells and tiny drop-like lesions in the corneal endothelium called corneal guttata.​
• Also, visual acuity testing with an eye chart that is done during a comprehensive exam can reveal decreased vision due to corneal swelling.
• As the disease progresses, the epithelial bullae can rupture, causing painful corneal abrasions and poor vision. If this occurs or if Fuchs’ dystrophy progresses to the point of causing significant vision loss, a cornea transplant usually is needed.​

How Is It Treated?

• Treatment for Fuchs’ dystrophy depends on the stage of the disease. In the early cases, vision often can be improved by removing excess water from the cornea with 5% sodium chloride (hypertonic) eye drops.​
• There is no cure for Fuchs’ dystrophy. However, you can control vision problems from corneal swelling. Your treatment depends on how Fuchs’ dystrophy affects your eye’s cells.​
• Early Fuchs’ dystrophy: Use an eyedrop medicine or ointment to reduce swelling of the cornea’s cells. Use a hair dryer, held at arm’s length, to blow warm air on your face. This helps dry the surface of your cornea.​
• For very poor vision or scarred corneas, you may need a cornea transplant.
  • Endothelial keratoplasty (EK): Healthy endothelial cells are transplanted into your cornea.
  • Full corneal transplant or penetrating keratoplasty: The center of your cornea is replaced with a healthy donor cornea.​​
  • Fortunately, in the majority of patients, the disease does not progress so far that corneal surgery is needed.​
    • Both are very successful with visual recovery in weeks to months. ​
    • The corneal tissue is held in place by an air bubble; occasionally more than one air bubble is needed. ​
    • Patients must lie flat on their backs after surgery to encourage the corneal tissue to “stick” to their own corneas.​
• If you have photophobia caused by corneal dystrophy, eyeglasses with photochromic lenses may be helpful to reduce your sensitivity to sunlight. Also, anti-reflective coating eliminates reflections in eyeglass lenses that may be particularly bothersome to someone with Fuch’s dystrophy.​
• If you have endothelial dystrophy and ocular hypertension, your eye doctor might recommend glaucoma eye drops to reduce your intraocular pressure (IOP). High eye pressure can damage the corneal endothelium, worsening Fuchs’ dystrophy.​
• In recent years, an advanced form of DLEK called femtosecond laser-assisted Descemet stripping endothelial keratoplasty (FS-DSEK) has shown encouraging results for treatment of the disease.​
• The progression of the FED from early to late stage may take from 10 to 20 years. 
• No therapy is required until the first symptoms appear​

Where Can I Learn More???

• Check out our cornerstone on this disease here.
• Learn more from The Corneal Dystrophy Foundation.