What is Fuchs' dystrophy and how can it put your sight at risk?
26 October 2021
What is Fuchs’ dystrophy?
Fuchs’ dystrophy (also known as Fuchs’ Endothelial Corneal Dystrophy, or FECD) is an eye condition that impacts your cornea, causing your vision to deteriorate over a long period. The cornea is the transparent layer at the front of your eye and it is irregularities and bumps on the cornea that lead to refractive errors. The health of the cornea is very important for your overall eye health and standard of vision, so Fuchs’ dystrophy can have devastating effects on your vision if left untreated. It can also cause discomfort, as well as impairing your vision.
At the back of your cornea is a layer of cells – this is called the endothelium and it is responsible for maintaining the correct amount of fluid within the cornea. This enables you to see well. As you get older, everyone naturally loses some endothelial cells. The loss is small-scale and does not typically affect your vision to the point that you need to worry about it. However, with Fuchs’ dystrophy, more endothelial cells are lost in a shorter time frame, leading to a build-up of fluid within the cornea. This in turn leads to increased corneal thickness and swelling, resulting in blurry vision and other symptoms.
Fuchs’ is a genetic disease; if a parent has Fuchs’ dystrophy, their child has a 50% chance of developing the condition in their lifetime. Interestingly, Fuchs’ is three to four times more common in women than in men. It typically occurs in both eyes and usually begins to display symptoms once people reach their 40s or 50s, although it can present earlier.
What are the symptoms of Fuchs’ dystrophy?
There are a number of symptoms of Fuchs’ dystrophy that sufferers of the condition are likely to experience. However, it’s important to note that some people with Fuchs’ never develop any notable symptoms so their condition is only diagnosed at a standard eye test, rather than as a result of them visiting an optician with vision issues.
Common symptoms include:
- Blurry vision
- Halos appearing around bright lights
- Light sensitivity
- Grit-like feeling in the eye
- Eye pain
- Poor colour contrast
- Worsening depth perception
- Varying vision throughout the day
The most common first sign of Fuchs’ dystrophy is blurry vision. This typically occurs because of a five step process:
- The endothelium deteriorates
- This causes small bumps to occur on the back of the cornea
- Fluid then begins to build within the cornea
- This results in swelling (known as corneal edema)
- The swelling leads to blurry or cloudy vision
(Source: Hopkins Medicine)
Your vision is likely to be blurry in the morning as the cornea swells as you sleep. This happens even in people who don’t suffer with Fuchs’ dystrophy, although the condition does heighten the problem. Throughout the day, some of the fluid that has built up in the cornea can evaporate, improving your vision as a result.
How is Fuchs’ dystrophy diagnosed?
As we briefly touched on earlier, people with Fuchs’ dystrophy are first diagnosed with the condition at an eye test. They will usually have noticed some visual changes and seek medical advice as a result, but some people won’t actually know they have the disease as it doesn’t affect their vision.
At the eye test, you would have a pachymetry test which measures your corneal thickness. People with Fuchs’ dystrophy tend to have thicker corneas so this measurement with a pachymeter is a great indicator when it comes to diagnosing the condition.
We also previously talked about the loss of endothelial cells and how this process is sped up by Fuchs’ dystrophy. A confocal/specular microscope examines your corneal endothelium to measure the number, density and shape of endothelial cells. This is known as an ECC test (Endothelial Cell Count test) and again provides an accurate indication of just how much your eye health has been impacted by Fuchs’ dystrophy.
Can corneal transplants treat Fuchs’ dystrophy?
Yes, corneal transplants are the best treatment for severe Fuchs’ dystrophy. Until the condition affects your vision or causes you pain, you won’t actually need any treatment. For less advanced Fuchs’ dystrophy, you could try using tinted glasses to help with any light sensitivity that may be causing you discomfort.
If you find that your condition is severe and it is impacting your vision on a daily basis, it is possible that you will need a corneal transplant. There are two types of corneal transplant which can be used to treat Fuchs’ dystrophy, DSEK and DMEK.
DSEK (Descemet's stripping endothelial keratoplasty) is the most common type of corneal transplant. This is a process whereby the recipient receives a new endothelium as well as stroma from the donor cornea.
DMEK (Descemet's membrane endothelial keratoplasty) is a corneal transplant which only relies on the endothelium and Descemet’s membrane from the donor, rather than the stroma too. DMEK corneal transplants actually transplant a thinner layer of tissue than occurs in DSEK, bringing a quicker recovery time and better visual results. There is some risk of rejection with all transplant operations, but this number sits at 7-8% for DSEK and only 1% for DMEK.
Corneal transplants to treat Fuchs’ dystrophy only remove and replace the deepest corneal layers. A small incision is made in the cornea to remove the innermost damaged layer. The new healthy cornea is inserted through this same incision before it is closed, either with stiches or on its own. Although the surgery itself takes less than an hour, it may be up to six months before you see complete visual improvement.
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