A corneal dystrophy is a genetic condition. It usually involves the gradual accumulation of an abnormal material such as lipids or cholesterol in the cornea. This causes the usually transparent, cornea – the ‘windscreen’ of the eye – to become translucent or opaque. In some forms of the condition, loss of vision may eventually occur.
Corneal dystrophies are hereditary. They generally occur in the first few decades of life and happen equally between men and women. The exception is Fuchs’ dystrophy: it is still unclear whether Fuchs’ is a genetic disorder; it usually manifests itself after the age of 50 and is more likely to occur in women.
If one of your parents carries a dominant gene for a corneal dystrophy, you have a 50% chance of inheriting the condition, so it’s important that you have regular examinations.
Conversely, neither of your parents may actually suffer from a corneal dystrophy, but they may be a carrier/carriers. If there is any genetic instance of a corneal dystrophy in either your mother’s or father’s family, related by blood (however distant), there is a chance you may inherit the same condition.
You may also suffer from a corneal dystrophy but be asymptomatic. This is why it is important you ensure that not only does your family tell you of a genetic predisposition, but you also ensure that your children are aware and tested.
Corneal dystrophy is not one, but a group of conditions and therefore each is categorised according to the layer of the cornea where it starts. Although there are five corneal layers, broadly speaking corneal dystrophies are split into three categories:
These affect the outer two layers of the cornea and include:
These affect the middle layers of the cornea and include:
These affect the bottom (innermost) layer of the cornea and include:
Treatment may vary for different forms of corneal dystrophies.
Mild symptoms may be treated with a wide range of lubricating treatments. The treatment of moderate symptoms may involve eye drops or ointments, the use of contact lenses, a temporary eye patch or bandaged contact lenses. As symptoms progress, there are a number of laser treatments.
Only in the most severe cases will a corneal transplant be necessary.
Although corneal dystrophies are rare, this disorder has a range of variations. Most are inherited and so, even though in the early stages it is mostly asymptomatic, anyone with a genetic disposition to a corneal dystrophy should see their GP or optometrist, where they can obtain a referral to seek a diagnosis from an ophthalmologist.