– The cornea
– Fuchs corneal endothelial dystrophy
– Being diagnosed
– What causes Fuchs dystrophy?
– How does Fuchs dystrophy affect sight?
– Can I do anything to slow down the development of Fuchs dystrophy?
– Cataracts and Fuchs dystrophy
Corneal dystrophies are inherited problems, which can affect the clearness of your cornea.
Your cornea is the clear part of the front of the eye wall. It is made up of a number of layers and is normally smooth and transparent (clear). It is also very strong.
The surface of the cornea is very sensitive. It contains many nerve endings and can detect even the smallest piece of dirt or fluff. It has a transparent skin layer that acts as a barrier between your eye and the outside world, helping to protect it from injury and infection.
Your cornea is important for sight. It bends and focuses light into the eye. Light is then focused by the eye's lens onto the retina, at the back of the eye. Your retina converts light into electrical signals. These are then sent to the brain where they are interpreted as the images we understand as sight.
Fuchs corneal endothelial dystrophy
Fuchs dystrophy affects the endothelium, the innermost layer of your cornea. The endothelium is a single layer of flattened cells that controls the movement of fluids and nutrients in and out of your cornea. As a normal part of getting older, a small number of endothelial cells are lost. This does not normally cause any changes in vision.
In Fuchs dystrophy, this process speeds up and more cells than usual are lost. Eventually, the endothelium doesn’t work well enough as a barrier preventing fluid soaking into the cornea or as a pump removing water from the cornea. This causes the cornea to swell due to the build-up of fluid, known medically as "oedema". This water-logging can affect vision. It is not certain why Fuchs dystrophy speeds up the loss of endothelial cells.
Fuchs dystrophy also causes deposits called guttata appear on the back of the cornea. These are miniature lumps which can only be seen with a microscope. They can cause light to be scattered, causing symptoms of glare.
Fuchs is the most common corneal dystrophy. It is usually diagnosed when someone is in their 40s or 40s. Women are three to four times more likely to develop Fuchs dystrophy. The reason for this is not known.
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Fuchs dystrophy develops slowly over 10 to 20 years and normally affects both eyes. It is often detected by an optician even when you haven’t noticed any changes to your vision. Your optician may mention Fuchs dystrophy to you because they can see changes to the back layer of the cornea when they examine your eyes. This does not mean you will go on to have problems with your vision and nothing needs to be done if you are seeing well.
What causes Fuchs dystrophy?
Fuchs dystrophy is a "dominant" inherited condition. This means that if you have Fuchs dystrophy, 50 per cent of your children will also have it. But because not everyone who has Fuchs dystrophy goes on to have problems with their vision, other family members carrying the gene may never experience any difficulties with their sight.
Because no treatment is required unless you are having problems with your vision, family members do not need to be screened and do not need any special additional care for their eyes.
How does Fuchs dystrophy affect sight?
When Fuchs dystrophy is first diagnosed you may not have any problems with your vision. A first sign that Fuchs dystrophy is affecting sight is normally that your vision is blurry when you wake up in the morning.
This blurring happens because the endothelium isn’t removing water from the stroma, the middle layer of the cornea, causing oedema (swelling with water). You may find that the blurriness improves as the day goes on. This improvement happens because once your eyes are open moisture is able to dry up from their surface.
Extra fluid in your cornea can make light uncomfortable and you may find it harder to see when it is very bright. You may also experience glare and see halos around lights. This can be more noticeable at night, for example, when you are driving.
The fluid in your cornea may also affect how well you can pick objects out against their backgrounds, particularly if they are a similar shade or colour. For example, reading yellow text on a yellow background. This is described as having reduced contrast sensitivity.
For some people, light scatter from guttata, the tiny lumps on the inside of the cornea due to Fuchs dystrophy, may be severe enough for someone to need a corneal transplant even though the cornea has not yet become swollen.
In the longer term
Eventually, some people can find their vision no longer improves as the day goes on. This is because they have lost more endothelial cells. Fluid now collects in the stroma and in the epithelium (the outermost layer of the cornea), causing these layers to become swollen all the time.
The epithelium has many nerve endings in it. As well as causing problems with sight, this swelling can cause your eyes to feel gritty and painful.
If you have a swollen or "oedematous" cornea you may also develop blisters on its surface. These are known as epithelial "bullae" (pronounced BULL-eye). If this happens it is known bullous keratopathy. If one of these blisters bursts, this can cause sharp pain and discomfort.
These blisters can also cause increased light sensitivity, glare and halos around lights. They can also make your eyes watery (teary).
If blisters develop, these can cause scarring in the stroma, which can eventually reduce vision in the affected eye. However, it is likely that if you do start to experience any of these symptoms you would receive a corneal transplant before this level of damage occurred.
For most people Fuchs dystrophy is a slow developing condition and it is possible to go for a long time without experiencing any of these symptoms.
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Can I do anything to slow down the development of Fuchs dystrophy?
At present there is no evidence that supplements or diet can help to slow down Fuchs dystrophy or prevent it from developing. There are no treatments that can prevent or reverse the loss of endothelial cells. However, the symptoms of Fuchs can be treated.
If Fuchs dystrophy isn’t affecting your sight, then you don’t need any treatment. If your vision is affected mainly in the mornings, clearing through the day, then saline solution in drops and ointments can sometimes help by drawing out fluid from your swollen cornea.
If corneal blisters (bullous keratopathy) develop then you may be prescribed tablets to help with the pain or discomfort they cause. You may also need to wear soft bandage contact lenses, worn day and night, to relieve pain by protecting exposed nerve endings on the surface of your cornea while you are waiting for a transplant.
Blisters make the shape of the cornea uneven. This affects they way that light is focused into the eye also causing problems with vision.
If the changes to your sight are starting to cause you difficulties, your specialist may recommend that you have a corneal transplant. Corneal transplants are extremely successful in treating Fuchs dystrophy.
A corneal transplant is surgery to remove all or part of a damaged cornea and replace it with healthy, clear cornea tissue from the eye of a donor who has died. It is possible to carry out transplants which replace all, or only some layers of your cornea, with healthy donor tissue.
Your ophthalmologist would be able to explore with you when it may be right for you to have a corneal transplant.
Types of corneal transplants
The most common corneal transplants used to treat Fuchs dystrophy only replace the innermost layers of the cornea. These types of procedures are known as "endothelial keratoplasty" or EK.
The most common EK transplant for Fuchs is called Descemet's stripping endothelial keratoplasty, often shortened to DSEK. This procedure is sometimes also known as a "DSAEK" where the "A" stands for automated.
In DSEK you receive a new endothelium, Descemet's membrane, a layer of the cornea found between the endothelium and the stroma, as well as some of the stroma from a donor cornea.
A newer type of EK transplant is called Descemet's membrane endothelial keratoplasty (DMEK). In DMEK you receive only the endothelium and the Descemet's membrane from a donor cornea. By transplanting a thinner layer of tissue in DMEK, recovery times are faster than for DSEK, the visual results are even better and the rejection risk is lower at only one per cent for DMEK, compared to 7-8 per cent for DSAEK and 12-13 per cent for a full thickness "penetrating keratoplasty" (PK) transplant.
DSEK and DMEK have short recovery times, usually only a few weeks or months. No stitches are needed and instead the new layers of donated tissue are kept in place with a temporary air bubble, which acts as a bandage, holding the transplant. This is either removed at the end of the surgery or left in place to help with the healing process. If this is the case, the air bubble is then harmlessly absorbed into your eye.
Less commonly in Fuchs dystrophy, if the stroma is scarred someone might need to have a full thickness transplant. This is where your whole cornea is replaced by a donor cornea. This type of transplant requires stitches and has a recovery period of about eighteen months. The medical name for this procedure is penetrating keratoplasty (PK).
If you need a transplant, the type that may be right for you is likely to depend on the layers of your cornea Fuchs dystrophy has affected.
How well does corneal transplant work?
Both EK and PK corneal transplants work very well in Fuchs dystrophy as Fuchs does not come back in the transplant.
Most people notice an improvement in their sight in the first six months after surgery. People who have had EK transplants are likely to experience improvements in their sight more quickly than people who have had PK. This is because EK is "keyhole" surgery which is quick to heal and does not require stitches.
After having a corneal transplant you will need to wear glasses or contact lenses to get the best possible vision. How much and how quickly your vision will recover after a corneal transplant can depend on the type of transplant you have had, as well as if you have any other eye conditions affecting your sight.
Corneal transplants are an effective treatment. But a transplant may need to be repeated if there are problems with transplant rejection. This occurs when your body’s immune system recognises the transplanted tissue as foreign. It is usually possible to treat corneal transplant rejection with anti-inflammatory drops, which reduce swelling. But repeated problems with rejection can lead to the transplant failing and the need for repeat surgery.
Although rejection is a risk and can affect about one in five of all transplants, the risk of rejection is reduced by using steroid eye drops. Across all types of corneal transplant, 75 per cent last at least five years and more than 50 per cent last up to ten years. Advantages for EK in addition to rapid recovery may include lower rejection rates and relatively easy repeat surgery, if this is required.
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Cataracts and Fuchs dystrophy
Both Fuchs dystrophy and cataracts are more common as you get older, and this means that they can often happen together.
Cataracts are a very common eye condition. As you get older the lens inside your eye gradually changes and becomes less clear. A lens that has turned misty, or cloudy, is said to have a cataract.
Over time a cataract can get worse, gradually making your vision mistier. Cataracts can be treated with a straightforward operation to remove the cloudy lens and replace it with a new artificial one, to enable you to see more clearly again. Read more information about cataracts and cataract surgery here.
Cataract surgery is usually very successful. But in people with Fuchs dystrophy, it sometimes needs to followed up by or combined with DMEK or a similar EK procedure.
Because the results of DMEK are so good, people who have Fuchs dystrophy and symptoms due to cataracts are normally now treated at the same stage in cataract development as those without Fuchs dystrophy.
If you are concerned about cataract surgery worsening Fuchs dystrophy, it would be important to discuss this with your ophthalmologist.
Fuchs dystrophy is a slow developing condition that affects both eyes. It is caused by an increased rate of cell loss from the innermost, endothelial, layer of the cornea. Although there is no cure for Fuchs, it may take many years for corneal changes to reach a level where they are seriously affecting your sight. Many people with Fuchs dystrophy never need any treatment.
In the early stages of the condition, when sight is not being affected, no treatment is required. Treatment can include saline drops, bandage contact lenses or a corneal transplant, which can effectively improve your sight.
If you are worried that Fuchs dystrophy may be affecting your vision, it would be important to discuss this with your optician or ophthalmologist.
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Being diagnosed with an eye condition can be very upsetting. You may find that you are worried about the future and how you will manage with a change in your vision. We’re here to support you every step of the way, and to answer any questions you may have – just get in touch with our Sight Loss Advice Service.
You may also want to consider joining Fuchs Friends, a UK-based voluntary internet support group for people affected by Fuchs dystrophy, which enables people to discuss their experiences and exchange information with each other.
Help to see things better
Ask your ophthalmologist, optometrist or GP about low vision aids, like a magnifier, and ask for a referral to your local low vision service. You should also ask whether you are eligible to register as sight impaired (partially sighted) or severely sight impaired (blind). Registration can act as your passport to expert help and sometimes to financial concessions. Even if you aren’t registered a lot of this support is still available to you.
Local social services should also be able to offer you information on staying safe in your home and getting out and about safely. They should also be able to offer you some practical mobility training to give you more confidence when you are out.
Our Sight Loss Advice Service can also give you practical guidance on living with sight loss, and our Online Shop has products that can make everyday tasks easier.
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