Fuchs’ (fooks) corneal dystrophy is a hereditary eye disease with symptoms that often become noticeable after the age of 50. Ultimately, it causes loss in vision which can be treated with a cornea transplant. To understand Fuchs’ you must first understand how the cornea works, since Fuchs’ initially only affects one single layer of the cornea.
The cornea is the clear window on the front of the eye and is comprised of three main layers—the epithelium, stroma and endothelium. The purpose of the epithelium is to act as a barrier to protect the cornea from dust, debris and bacteria. The stroma is the middle layer and makes up 90% of cornea thickness, mostly of collagen and other structural materials. Its purpose is to give the cornea its strength and dome-like shape. The endothelium is just one layer of cells located on the Descemet membrane (blue line in illustration above) and its job is to provide the appropriate balance of fluid in the cornea, keeping it thin and crystal clear.
What does Fuchs' look like?
These two images show endothelial cells, the cells that make up the endothelium. The image on the left depicts a healthy endothelium where hexagonal cells are clearly outlined. The image on the right shows an eye with guttae, which would be diagnosed as Fuchs' dystrophy.In patients with Fuchs’, the endothelial cells slowly deteriorate as tiny bumps called guttae accumulate on the Descemet's membrane. When the endothelial cells develop these guttae, the surrounding cells become damagedand cannot work properly. Since the remaining cells cannot keep up with pumping fluid, the cornea begins swelling (known as corneal edema). As a result, the cornea becomes thicker and cloudy, resulting in vision problems. In advanced cases, tiny blisters can form on the surface of your cornea which can be painful, so it is important to seek treatment prior to severe progression.
If you have Fuchs’ dystrophy, one of the first signs may be that you begin to notice glare with headlights at night or in bright sunlight. As the Fuchs’ dystrophy progresses, your vision may become foggy or blurry in the morning and clear as the day progresses. This occurs because evaporation of fluid from the cornea is decreased while your eyes are closed during sleep, and accumulation of fluid in the cornea during the night results in corneal swelling. This early stage can be treated with a special salt solution or ointment to help pull the water out of your cornea. However, as the Fuchs’ progresses, your vision will stay blurry longer during the day, and eventually your vision may not clear at all.
Additional Symptoms:
- Glare and sensitivity to light
- Poor vision upon awakening with improvement later in the day
- Eye pain
- Foggy or blurred vision
- Seeing colored halos around lights
- Difficulty seeing at night
Who is at risk?
Fuchs’ dystrophy exhibits dominant inheritance, which means that roughly half of an affected person’s offspring may inherit it. However, the degree to which the condition is expressed is variable, so some family members may be more severely affected than others. The Cornea Research Foundation is collaborating with researchers at Case Western Reserve University to determine the genetic basis of Fuchs’ dystrophy.
Fuchs’ dystrophy tends to show up later in life and symptoms are uncommon before the adult years. The initial findings in Fuchs’ dystrophy are corneal guttata, which appear as dark spots on the corneal endothelium. As the condition progresses the critical endothelial cells start to die off. The normal function of these cells is to pump water out of the cornea. As they decrease in number and fail to function properly, fluid builds up in the cornea causing it to swell and become cloudy.
What are the treatment options?
When you first begin experiencing symptoms your doctor may recommend a special salt solution which helps pull the fluid out of your cornea to provide clearer vision. As the Fuchs' progresses, your vision will ultimately stay blurry longer during the day and eventually may not clear at all. At that time, a cornea transplant can restore your vision.
In the past, there was just one option for transplants, called penetrating keratoplasty (PK), which involves the surgical removal of the central two-thirds of the damaged cornea. It is then replaced with healthy donor tissue. The new tissue is held in place typically by many sutures, 16 would be an average number though it varies by surgeon. The full thickness transplant does have the potential to provide clear vision after healing, however, the healing time can be upwards of a year and in some cases, the sutures may never be removed. The recipient must be careful with the eye to ensure the wound doesn’t rupture, even many years after a transplant. Since 20 percent of PK grafts reject, many patients require more than one surgery.
To give you better vision and faster recovery, the Cornea Research Foundation has been working since 2001 to pioneer a new option called endothelial keratoplasty. We have found that you can get the best possible vision and fastest recovery with a variation known as Decemet’s Membrane Endothelial Keratoplasty (DMEK), which our studies have shown provides optimal visual results with less adverse risks than with PK.
The cornea is the thickness of a credit card, and DMEK replaces less than 1/20th of that thickness. With DMEK, only the damaged endothelium of the cornea is replaced. This tissue (see layers of the cornea figure at the top of the page) is carefully removed through a small incision, and the replacement donor tissue is rolled up, inserted and flattened out. Rather than sutures, the tissue is held in place with an air bubble, resulting in faster healing. Notice the front surface of the cornea remains smooth and intact with DMEK which leaves the eye much stronger and less prone to accidental injury.
These photo
s compare how the eye appears after each transplant type (full thickness vs. DMEK). Notice how much healthier the DMEK eye (Figure B) looks with the single suture to the left compared to the PK eye (Figure A) with many sutures. Both photos were taken just 7 days after surgery.
What kind of results are typical with DMEK?
Visual recovery is much faster with DMEK because the air bubble that holds the tissue in place while it attaches is much less invasive than sutures. In some cases, patients may experience visual acuity as good as 20/20 just a few days after surgery with glasses. Most importantly, the rejection risk is 15 to 20 times lower with DMEK. Such low rejection is unprecedented and essentially eliminates one the main reason that transplants fail. In summary, research has shown that DMEK is now an excellent treatment option for patients with Fuchs’ dystrophy. Be sure to check out our publications page for updated study results of research findings involving DMEK.
There is a new procedure being done in the United States called Descemet's Stripping Only (DSO) that may be another treatment option for those with Fuchs' dystrophy. Visit the DSO page to learn more.
When to seek treatment:
Once you find that your vision is impairing your quality of life or causing you to cut back on activities, such as night driving, it is time to replace the diseased layer. Fortunately, we now have a minimally invasive way to do that with a transplant procedure known as DMEK.
It is important to be your own advocate and ensure you are receiving the best care with the most up-to-date surgical methods. DMEK is becoming available from a growing group of skilled surgeons in different parts of the country and the world. One needs to ask how many they have done and what their results are. Ask questions like what is their percentage of paetients with clear grafts? What is the percent of cases that need to be redone? How long do they have patient follow up records on? If you want to visit our site for a consulation with one of the pioneers of this type of surgery, click here to learn more about traveling to Indianapolis.