Ophthalmology

Corneal dystrophy

What is corneal dystrophy?

Corneal dystrophies are a group of hereditary diseases of the cornea. It is a non-inflammatory disease that usually affects both eyes. In most cases, it is noticeable through a reduction in the transparency of the cornea and a deterioration in vision. Their maximum age is between the ages of 10 and 50. The corneal dystrophies are divided into different forms, each affecting different areas of the cornea. Mutations in various genes are the cause.

causes

Corneal dystrophies are hereditary (hereditary) diseases. The cause are different mutations in different gene sequences. The gene sequences have been localized in recent years through intensive medical research, which has led to a better understanding and better diagnostic and therapeutic options. Molecular testing can diagnose the specific form of corneal dystrophy in the patient and treat it accordingly. These diseases are often passed on from generation to generation in a family.
Corneal dystrophies are non-inflammatory diseases, ie. they do not arise as a result of previous inflammation or other disease of the cornea. Nor can they occur as a result of accidents or injuries. Corneal dystrophies are often discovered incidentally in an ophthalmological examination in physically healthy people.

This article might also interest you: Astigmatism

What forms are there?

There are many different forms of corneal dystrophy, each affecting different areas of the cornea. They are classified according to their gene mutation and named after their typical appearance. According to the localization, they can be divided into 3 groups. One group mainly affects the superficial layers such as the epithelium, another the middle stroma layer and the third group the posterior layers of the cornea such as the endothelium.

Read more on the topic: Cornea of the eye

The most common form is Fuchs endothelial dystrophy. It affects the endothelial cells on the inside of the cornea and leads to an increasing breakdown of these. It mainly affects women over the age of 50. It leads to impaired vision and can be treated with eye drops or, in the worst case, with a cornea transplant.
Map-dot fingerprint dystrophy affects the basement membrane of the epithelium. This form occurs at a young age and leads to symptoms such as deterioration of vision, eye pain, and blurred vision.
Other forms are: granular corneal dystrophy, latticed corneal dystrophy, honeycomb corneal dystrophy, macular corneal dystrophy, epithelial dystrophy.

Find out more about the topic: Corneal transplant

How is the inheritance?

Corneal dystrophies represent a group of different forms of disease, which in turn have different inheritance patterns. Depending on the mutation, they are inherited as an autosomal dominant, autosomal recessive or X-linked recessive trait. Affected patients can undergo genetic counseling, which can inform them about treatment and prognosis, as well as information passed on to the children.

diagnosis

If there is a decrease in the transparency of the cornea and, in particular, clouding occurs in both eyes at the same time, corneal dystrophy should be considered. The ophthalmologist can examine the cornea using a slit lamp examination and determine possible structural changes or opacities.

In addition, he can take a sample during the examination and examine it under an electron microscope. Particularly in patients who have relatives with corneal dystrophy, a regular ophthalmological examination should be carried out in order to be able to diagnose a possible corneal dystrophy as early as possible. A molecular test of the genes can also be useful to find out the exact form of the corneal dystrophy.

What are the symptoms of corneal dystrophy?

Many corneal dystrophies cause few or very late symptoms and are often not recognized by the patient. The diseases are often discovered in physically healthy patients during an ophthalmological examination.
When symptoms occur, the patients often notice a deterioration in vision first. This increases more and more over time. The deterioration in vision is often subject to a period.

Some forms have severe vision problems, especially in the morning, but these decrease as the day progresses. In addition, there can be long pauses without symptoms between the symptoms. In addition, the cornea becomes cloudy, which is initially invisible but which can get worse over the years.
With corneal dystrophies, which particularly affect superficial parts of the cornea, i.e. the epithelium etc., severe eye pain also occurs.

Also read the article on the topic: Corneal opacity

Treatment / therapy

The treatment of corneal dystrophies depends on the particular form. It is therefore important to diagnose the exact form of corneal dystrophy using molecular tests before starting therapy. Some forms do not require treatment.
In some forms, dehydrating eye drops or ointments are sufficient, such as map-dot-fingerprint dystrophy or Fuchs endothelial dystrophy. The special eye drops draw liquid from the cornea, which leads to an improvement in eyesight.

In the case of more severe forms of corneal dystrophies, however, only so-called keratoplasty, i.e. a transplant of the cornea, will ultimately help. The diseased cornea is replaced by a cornea from a dead donor. Due to the fact that the cornea contains few immunocompetent cells, a rejection reaction occurs relatively rarely. Additional immunosuppression by means of medication is only required in rare cases. A transplant has a good success rate and improves eyesight in most people.

Course of the disease

Corneal dystrophy is a progressive disease, ie. its severity increases over time.
Some forms do not cause any symptoms for the patient and therefore have no life-threatening effects. Other forms lead to symptoms very late and worsen even a little. The severe forms of corneal dystrophy lead to impaired vision and eye pain very early on. Often there are symptomatic phases in these, often for years, so that in the end only a corneal transplant helps to counteract blindness.

forecast

Corneal dystrophy is not a life-threatening disease. For many patients it does not lead to any restrictions in daily life. Early diagnosis and treatment can reduce complications. Only in rare cases is there a severe impairment of everyday life due to impaired vision. In such cases, however, a corneal transplant can, in most cases, lead to a cure.