Fuchs’ dystrophy

Fuchs’ dystrophy is a form of corneal dystrophy that tends to strike people in their fifties and sixties (although early signs can sometimes be seen in patients as young as 30) and affects women three times more often than men. Fuchs’ dystrophy is bilateral—i.e., it affects both eyes—and is caused by the loss of cells of the endothelium, which is the innermost layer of the cornea.

Fuchs’ dystrophy is named after the ophthalmologist Ernst Fuchs (1851–1930), who first described the condition in 1910. Fuchs considered his syndrome to be a disease of the epithelium (the outer layer of the cornea), but by the 1920s it was understood to be an endothelial condition.

This condition is not common—Fuchs estimated the incidence to be about one person in every 2,000. It is more prevalent in Europe and among people of European descent.

List of Symptoms of Fuchs’ Dystrophy
The early stages of Fuchs’ dystrophy are characterized by blurry vision in the morning that clears up within 30 to 60 minutes of waking. Sufferers eventually begin to experience other forms of visual distortion—including poor night vision and the appearance of halos around lights—and become extremely sensitive to light (this symptom is called photophobia). The cornea eventually develops a cloudy appearance, and tiny, painful blisters begin to form on the epithelium. If left untreated, Fuchs’ dystrophy can eventually cause blindness.

You should see an eye care professional if you are over 40 and suffering from:

• Chronic eye pain
• Light sensitivity
• Blurred vision—especially if it occurs upon waking and clears up as the morning progresses
• The appearance of halos around lights
• The persistent sensation of a foreign body in the eye

What Causes Fuchs’ Dystrophy to Develop?
The symptoms of Fuchs’ dystrophy are caused by the gradual loss of cells lining the endothelium. The function of these cells is to prevent the buildup of fluids by pumping them out, thereby helping to maintain the transparency of the cornea. As the disease progresses and these cells deteriorate, overnight fluid accumulation begins to cause blurred vision upon waking, which gradually improves throughout the day. This morning blurriness is exacerbated by the natural tendency of the cornea (even in a healthy eye) to thicken during the night from fluid retention. Ordinarily, this excess fluid begins to dissipate into the tear film after we awaken. In patients suffering from Fuchs’ dystrophy, however, the cornea retains this nighttime thickness even upon waking, and morning blurriness lasts longer and longer, until visual clarity disappears altogether. Fluid continues to collect under the epithelium, leading to constant discomfort and occasional pain, and eventually causing painful blisters. The swelling of the epithelium alters the curvature of the cornea (producing distortion) and causes a haze to appear, which obscures vision.

In most cases, Fuchs’ dystrophy is genetic in origin, although the disease does occasionally present itself in patients with no family history of it. These cases are considered idiopathic, a medical term that means, “of unknown cause.” If either of your parents suffers from Fuchs’ dystrophy, there is a 50 percent chance that you will also develop it.

Various Risk Factors of Fuchs’ Dystrophy
There are only a few known risk factors for Fuchs’ dystrophy:

• Age—the disease rarely strikes anyone under the age of 50.
• Gender—women are affected more often than men.
• Family history—those who have first-degree relatives (parents or siblings) with this condition are considered to be at risk.

How is Fuchs’ Dystrophy Treated and Diagnosed?
If your doctor suspects that you suffer from Fuchs’ dystrophy, he or she will subject you to a number of tests. Your visual acuity will be tested with an eye chart, and you’ll be given a glare test to determine how badly bright light interferes with your ability to see. You will also be given a slit-lamp examination, and your doctor may want to administer a corneal pachymetry, an ultrasound test used to measure the thickness of your cornea. Eyedrops can be prescribed that can reduce the amount of fluid that accumulates in the cornea, but ultimately the only way to cure Fuchs’ dystrophy is with a corneal transplant.

There are two ways of performing such a transplant: the entire cornea can be replaced, or the surgeon can replace only the compromised endothelium with a procedure known as posterior lamellar endothelial keratoplasty or deep lamellar keratoplasty (DLK).

Fuchs’ Dystrophy and its Relationship with Cataracts
Fuchs’ dystrophy is associated in some ways with cataracts. People suffering from Fuchs’ dystrophy are at risk of developing cataracts as their dystrophy worsens, and there is a risk that performing cataract surgery on a patient with Fuchs’ dystrophy can worsen the disease by damaging the fragile endothelial cells, which are already compromised by the disease. In patients over the age of 40 whose anterior (front) eye chamber is considered shallow (less than three millimeters), there is a risk that a cataract may develop following corneal surgery, even if the lens is clear prior to the operation. The preferred way of handling such cases is to address both the cataract and the corneal transplant simultaneously, in a single procedure.

What Is the Overall Prognosis for Fuchs’ Dystrophy?
Following corneal transplant surgery, the short-term prognosis for this condition is excellent, although some studies suggest that the transplanted cornea may not hold up over time; there is also the possibility that the transplant may be rejected. Patients who have had corneal transplant performed for Fuchs’ dystrophy also sometimes suffer astigmatism.

Talking to Your Doctor
Here are some questions you can ask your doctor about Fuchs’ dystrophy:

• Given my family history, what are the chances that I will develop this condition?
• Is there a chance that cataract surgery will worsen my condition?
• Is there a chance that my corneal transplant will cause me to develop cataracts?
• My vision is fine right now, and I have no family history of Fuchs’ dystrophy; is it still possible that I will develop this condition when I get older?