Definitions of Keratoconus

Definitions of Keratoconus

Keratoconus is a progressive thinning and deformation of the cornea. The cornea protrudes cone-shaped. Keratoconus is often accompanied by other diseases and sometimes also by genetic disorders.

What is keratoconus?

Keratoconus can often only be diagnosed when noticeable myopia has already developed.

Keratoconus is characterized by the cone-shaped deformation and thinning of the cornea of ​​the eye. Both eyes are always affected. However, it is possible that the severity of the deformation is different in both eyes. The disease usually begins in one eye. A little later it spreads to the other eye. Keratoconus is characterized by two important features. See AbbreviationFinder for abbreviations related to Keratoconus.

On the one hand, the cornea is becoming thinner and more pointed, and on the other hand, visual acuity constantly decreases over time. Patients become short-sighted. A complete correction with a visual aid is not possible. This is due to the irregular bulging of the cornea. Astigmatism is also known as astigmatism. Keratoconus can progress in phases.

But there are also cases with a flowing and continuous protrusion of the cornea. The disease is very rare. Keratoconus affects one in every 1,000 to 2,000 people in the West. Around 40,000 people are affected in Germany. However, the prevalence is slightly higher in the Middle East. The disease usually begins between the ages of 20 and 30. However, it can also occur much earlier (in childhood) or much later (between the ages of 40 and 50).


The causes of keratoconus are not fully known. There are indications that it occurs in connection with certain genetic diseases such as Down syndrome, monosomy X, Ehlers-Danlos syndrome or Marfan syndrome. However, the development of keratoconus has also been observed in the context of atopic eczema, hay fever or other allergic diseases.

Structural studies of the cornea have revealed changes. The arrangement of the individual collagen lamellae is probably destroyed by a proteolytic degradation process. Several causes can lead to this. Either there are genetic changes or the eye is affected by various external stresses such asstrongRubbing or environmental factors affected.

At least these factors act like an initial event. The intraocular pressure increases and the tissue weakness of the cornea continues to increase. As a result, the curvature of the cornea continues to increase. A cycle is set in motion that is very difficult to stop. The disease can become acute if tears occur in the posterior cornea. Then fluid gets into the anterior chamber of the eye, which manifests itself in a rapid clouding of the cornea. In this case, the patients can only see as if through fog. However, this so-called hydrops develops back on its own.

Symptoms, Ailments & Signs

Keratoconus begins insidiously. Those affected have to constantly adjust their glasses. You sometimes see things twice. Sometimes it can only be in one eye. Furthermore, shadows appear on objects and letters, as well as star-shaped rays and streaks from light sources. Keratoconus lines with a yellow-brown or green-brown color appear, which completely or semicircularly surround the corneal cone.

Furthermore, tears can occur in Descemet’s membrane, which become visible as so-called Vogt’sche lines. In the advanced stage, acute keratoconus often develops, which represents water retention in the cornea. This heals after a few months with scarring. Keratoconus is divided into four stages, which document the severity of the corneal thinning and astigmatism.

Important symptoms of the disease are the occurrence of ghosting in vision, multiple images, distortions, constantly red eyes, tense facial muscles, intolerance to cold, dry or stuffy air, sensitivity to light, seeing halos, limited vision at night, changes in position or even falling out of the contact lenses, stargazing and streaks when reading. Allergies, asthma, rheumatism, neurodermatitis or dry eyes are often observed as concomitant diseases.

Diagnosis & course of disease

Keratoconus can often only be diagnosed when noticeable myopia has already developed. Sometimes the diagnosis is also made during a routine examination by an ophthalmologist. Signs of the disease result from frequent adjustment of glasses. However, the cause of these eye problems is often not recognized immediately because keratoconus is very rare.

Among other things, a retinoscope is available as a diagnostic device, which can detect the well-known fish-mouth effect in keratoconus. Furthermore, various devices are used to measure the corneal radii, corneal layers or corneal thickness. In addition, the surface structure of the cornea is recorded and the cross-section of the front part of the eye is recorded.


As a rule, keratoconus causes discomfort in the eyes. The affected person suffers primarily from visual problems and in the worst case can also go completely blind. The cornea is also damaged. The symptoms significantly reduce the quality of life and everyday life of those affected.

It is not uncommon for visual problems to lead to mental disorders or depression. Young people in particular often suffer severely from vision loss. Night blindness also occurs in most cases. The patients also suffer from an increased sensitivity to light and are therefore restricted in their everyday life. Blurred vision also occurs. As a result, in some cases the person concerned can no longer carry out their professional activities, also because they usually have to struggle with a loss of concentration.

In some cases, no direct treatment is necessary and the person concerned can compensate for the symptoms with contact lenses. Furthermore, interventions with a laser can also be carried out. In most cases, this only occurs in adulthood. There are no particular complications and theLife expectancyof the patient is not reduced by this disease.

When should you go to the doctor?

As a rule, a doctor should always be consulted for keratoconus. In the worst case, the disease can lead to the death of the affected person. Early diagnosis and treatment have a positive effect on the further course of the disease. See a doctor if the person’s vision changes frequently and gets worse over time.

Double vision or blurred vision can also indicate keratoconus and should be examined by a doctor. In many cases, the affected person’s cornea turns green or yellow. Eyes are red and objects may appear distorted or misshapen. If these symptoms persist and do not go away on their own, you should definitely consult a doctor. Asthma can also indicate keratoconus.

If you have this condition, you should always see an ophthalmologist. In acute emergencies, the person concerned can contact a hospital. The life expectancy of the patient is not negatively affected by the disease.

Treatment & Therapy

The treatment of keratoconus consists of the constant adjustment of glasses or the insertion of contact lenses. There is still no agreement on the best treatment method. With contact lenses, it can happen that they slip or even fall out if the cornea has already changed further. Some doctors therefore try to regulate the problems through constant glasses correction.

According to unconfirmed observations, contact lenses are said to accelerate the curvature of the cornea. However, other doctors have also reported the opposite. The use of contact lenses is intended to stop the curvature. So many different contact lenses are used. In individual cases, a corneal transplant is also performed.

Outlook & Forecast

The everyday life of those affected is often affected by symptoms such as sensitivity to glare, double vision and rapidly changing eyesight. The latter often happens within a few days, which means that correcting the eyesight with glasses only leads to short-term success. In order to compensate for this deficit, it helps to have glasses in different prescriptions in stock and to use them as needed.

After consultation with the doctor treating you, there is also the option of combining contact lenses with the existing glasses and thus being able to react quickly and extremely flexibly to a change in vision. Due to the increased risk of infection with keratoconus, absolute hygiene and regular contact lens changes must be observed.

Changes within the apartment also enable a further increase in the quality of life. To do this, possible sources of interference must be eliminated. Incorrectly installed lamps or lamps that are too bright lead to unpleasant stripes in the field of vision for many of those affected or to unpleasant glare due to the high sensitivity to light. If these effects occur at the workplace, the patient should not hesitate to address this to his or her superior and develop a possibility together with him to remedy the situation. Otherwise, the ability to work is sometimes significantly restricted due to a reduction in the ability to concentrate and can lead to an inability to work at this workplace.


Since the exact causes of keratoconus are not known, no concrete recommendations can be given for its prophylaxis. In general, however, those affected are advised to drink plenty of fluids and exercise frequently in the fresh air.


Follow-up care for keratoconus is closely related to prevention. Among other things, those affected should drink enough fluids and go out into the fresh air to protect their eyes. The frequent changes in vision can be mitigated in everyday life by switching off sources of interference. It is helpful to adjust the working and living environment accordingly.

Too bright light or unfavorable lighting increase the feeling of not being able to see properly. With better lighting, however, patients no longer feel as badly affected. In order to compensate for the varying visual acuity, it is also advisable to use several pairs of glasses.

This makes it easier for patients to deal with the visual problems. However, this requires precise consultation with the ophthalmologist. If necessary, they can speak to an optician to find a satisfactory solution for those affected. He may even recommend the combination of glasses and contact lenses.

Proper eye hygiene is also very important. By taking appropriate measures, patients can protect their eyes and prevent possible inflammationprotect. In this way, negative effects of infections on the eyesight can be avoided.

You can do that yourself

Patients with keratoconus suffer from the often rapidly changing visual acuity and various symptoms such as sensitivity to glare and double vision, which may interfere with everyday life. In order to maintain the usual quality of life, patients first try to adapt their living environment to the disease and eliminate certain sources of interference. These include, for example, lamps that are attached in an unfavorable position or that are simply too bright, which leave streaks in the field of vision of many patients with keratoconus and are also unsuitable due to the sensitivity to glare.

Since the visual acuity of those affected often changes within days, both in the direction of improvement and deterioration, owning several pairs of glasses makes it easier to manage the condition. Some people even combine contact lenses with glasses, although such practices must be clarified in any case with the attending ophthalmologist and, if necessary, with the optician. In this way, patients are able to react flexibly to the variable visual acuity.

In addition, eye hygiene plays a relevant role in maintaining the health of the visual organs and thus the general well-being of patients. By means of adequate hygienic measures, those affected protect their eyes from infections that may have a negative effect on the course of keratoconus.


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