Aniridia

Under Aniridia, also under the medical synonyms Iris aplasia and Irideremia known, is a congenital defect of the iris, iris, of both eyes. It is a rare hereditary disease that can also be associated with diseases in other parts of the body. The disease is considered incurable, but general life expectancy is not restricted.

What is aniridia?

Literally translated the term means aniridia without iris. It refers to the partial or complete absence of the iris. It is a genetic malformation of the organ of vision with complex influences on further development during adolescence.

Because the iris is partially absent in both eyes or is not present at all, the pupils cannot close or cannot close properly and regulate the incidence of light in the eyes, as is always the case with a person with normal vision. In the case of the genetically caused visual disorder, the eyesight of those affected is always severely impaired, and in the case of fulminant disease processes, complete blindness can also occur.

But there are also milder forms known in which those affected have almost no problems and can even acquire a driver's license. In the course of adult life, patients not only suffer from irideremia, but also from a variety of comorbidities that can, but do not have to, manifest themselves over time due to the genetic defect. Only the doctor can judge whether a new symptom is directly related to the absence of irides.

causes

The causes of aniridia lie in a genetic defect, a so-called chromosomal aberration. This genetic defect is innate and will accompany those affected for a lifetime. It is known from human genetic examinations from blood samples of those affected that there is a defect in the 11th chromosome.

The affected PAX6 gene is on the 11th chromosome and is considered to be the cause of the disease. The malfunction of this gene causes a delay in development in both eyes, so the full maturation of the eye function is completed too early and is not completed by the beginning of birth. It is a so-called autosomal dominant chromosomal dysfunction.

The risk of developing aniridia is statistically 1: 100,000, both sexes are equally affected. In the special form of so-called sporadic aniridia, the rare chromosome mutation occurs in a child whose parents are not affected. Every third case of iris missing is such a de novo mutation.

In both forms, the gene plays a role in the development of both eyes, which is why both eyes are affected by the disease. Nevertheless, there are also few individual cases documented in the world medical literature in which only one eye was affected by aniridia.

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Symptoms, ailments & signs

A lack of lumbar stem cells causes a variety of symptoms that affect the cornea of ​​the eye, such as chronic and difficult to treat keratitis. Whether isolated aniridia or aniridia is present in the context of other genetic abnormal developments, for example a WAGR syndrome, can only be found out on the basis of further human genetic differential diagnostics. The diagnosis is usually made by the pediatrician immediately after the birth.

Many patients complain of visual disturbances such as double vision or blurred vision. Often the vision is limited overall and the person concerned suffers from side effects such as dizziness or headaches. Furthermore, aniridia can lead to chronic keratitis. Such corneal inflammation manifests itself in light sensitivity and the characteristic clouded cornea.

Eye pain and dry eyes can also occur. If photophobia has already developed as a result of the aniridia, there are also signs such as involuntary eye movements, reddening of the eyes and inflammation. The increased intraocular pressure can cause irreversible damage to the optic nerve. This can lead to a complete loss of vision, which is heralded by restrictions in the field of vision, flickering and other symptoms.

The heavily clouded lens can cause side effects such as constant headaches or malaise. Externally, aniridia can be recognized by the visible enlargement of the iris and the lack of iris tissue. The iris appears almost completely monochrome and is usually dark gray to black. Some people experience bleeding or inflammation. The diagnosis can be made quickly based on these symptoms.

Diagnosis & course

The course of aniridia is always protracted and chronic, so that patients suffer from the disease itself and its consequences for the rest of their lives. Few of those affected develop no other side effects apart from the actual poor eyesight.

So-called photophobia is typical, this general light oversensitivity makes the visual process difficult and is also accompanied by vegetative accompanying symptoms such as constant headaches or malaise. Those affected also suffer from constant involuntary eye movements, the so-called nystagmus.

The increased intraocular pressure, narrow-angle glaucoma, can lead to irreversible damage to the optic nerve and consequently to complete loss of vision. In most aniridia patients, the lens is moderately to severely cloudy, which is known as a cataract.

Complications

The aniridia cannot be cured, but there is no lower life expectancy for the affected people. Most patients have poor eyesight due to aniridia. This is usually already present in childhood and is not acquired in the course of life. The aniridia also creates a strong sensitivity to light.

Bright light leads to pain in the eye and affects the visual process. Those affected cannot cope with everyday life without a special visual aid and are dependent on it. The strong sensitivity to light causes severe headaches and dizziness.

Most of the time, the patients also experience eye movements that cannot be controlled arbitrarily. In the worst case, it can lead to a defect in the optic nerve, whereby the patient loses his eyesight and becomes blind.

Treatment is not possible. However, it can limit symptoms such as poor eyesight or headaches relatively well. The doctor may also prescribe special glasses or contact lenses to help alleviate the symptom. There are no further complications, but the patient's life is limited.

When should you go to the doctor?

As a rule, aniridia is determined and diagnosed by a pediatrician immediately after the child is born or at the latest. For this reason, the doctor usually does not have to be visited again. Direct treatment of this disease is also only possible to a limited extent. Those affected suffer from severe visual problems and poor eyesight.

If, therefore, visual problems occur unexpectedly or for no particular reason, they must be treated by a doctor in any case. Treatment by a doctor is also necessary for photophobia. It is not uncommon for patients to also suffer from involuntary movements of the eyes, which can significantly limit everyday life. Cloudiness of the lens can also be a typical complaint of aniridia and should therefore be treated by a doctor in any case.

It is not uncommon for aniridia to occur with other diseases, so that early treatment can have very positive effects on the general condition of the patient. Those affected can also suffer from kidney problems or a tumor. If there are problems with the kidneys, these must also be examined by a doctor.

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Treatment & Therapy

Although the cause of iris aplasmia is clearly known, unfortunately, until now, those affected cannot be treated with causal, i.e. cause-related therapy. All treatment measures are based on the one hand on the degree of severity and on the other hand on the constantly changing symptoms of the patient.

Typically, more and more symptoms appear as the disease progresses, so that treatment is lengthy, time-consuming and also cost-intensive. Adults with aniridia receive training on how to behave and adapt to their surroundings. For example, sunglasses with extreme protective glasses and tints of 80 percent are required.

Every child with aniridia should be genetically examined as soon as possible and receive regular eye care. Regular ultrasound examinations of the kidneys are also required to rule out a so-called Wilms tumor. In order to completely prevent the incidence of light, selected sufferers can wear Aniridie Spezial contact lenses with an artificial iris and fixed pupil. Surgical interventions can only be carried out in certified eye centers.

Outlook & forecast

The prognosis of aniridia is to be classified as unfavorable. To this day, the congenital disease cannot be cured with the medical options available. The development of the eye comes to an early end and cannot be regulated by the administration of hormonal preparations or an operation. At the same time, symptoms may worsen under certain circumstances.

Complications such as an increase in internal pressure in the eye, clouding of the lens and cornea can lead to an increase in symptoms. This goes hand in hand with a further reduction in the already weakened eyesight. In addition, there is a risk that further diseases or a malfunction of the kidney function develop. This reduces the chances of recovery considerably.

With an early diagnosis and a quick start of treatment, targeted therapies to improve eyesight can bring about slight relief. This creates the best possible development of vision under the given circumstances. In addition, visual aids can lead to further but manageable improvements in vision.

The prognosis prospects for a slight genetic defect are also low. Although there are very few impairments in everyday life, there is still the risk that the existing symptoms will worsen in the course of life.

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prevention

It is not possible to prevent this hereditary eye disease. It has been found that an amniotic fluid test is also not suitable for detecting this malformation of both eyes in the unborn child.

Living with aniridia by adapting to rapidly changing light conditions or to prevent painful glare can only be made easier by consistently implementing the special rules of conduct and by adapting the surfaces in the work or school environment. Because every sensation of glare is painful for those affected, can reduce visual acuity and lead to movement insecurities.

Aftercare

So far, aniridia can only be partially compensated for. The aftercare therefore goes hand in hand with the actual treatment. As part of the therapy, the patient receives light protection goggles that have to be regularly adjusted to the current visual strength. Follow-up care can also include genetic clarification of the cause.

Depending on the trigger, the patient may need to have further examinations. Follow-up care ensures that the aniridia develops as planned and that no complications occur. If there are visual problems or other problems in the eye area a few months after the treatment, a follow-up is necessary.

People with aniridia need to have an ultrasound of their kidneys every three to six months, as the disease is associated with an increased risk of Wilm's tumor. If the tumor is detected early, there is a 94 percent chance of recovery. Patients should take the necessary examinations to identify any tumors at an early stage and improve the chances of recovery.

The regular checkups must be carried out for a lifetime. The doctor responsible can provide further details on the necessary follow-up checks and other follow-up measures and also advise the patient on suitable visual aids.

You can do that yourself

There are no preventive measures for this inheritable eye disease. Even an amniocentesis cannot clarify whether the malformation of the eyes is present in the unborn child. Since people affected by aniridia have an increased risk of developing glaucoma and cataracts, ophthalmologists and opticians should ensure that their visual function is maintained at regular checkups.

The usual therapy consists in the adaptation of individual light protection glasses with a special edge filter immediately after the birth of the person concerned. From around the age of two, nearsightedness or farsightedness can be compensated for with glasses. Normal contact lenses should definitely be avoided. In order to completely prevent the incidence of light, however, patients can wear special aniridia contact lenses with an artificial iris and a fixed pupil. Even if the disease cannot be treated, at least the symptoms, i.e. poor eyesight and headache, can be alleviated relatively well.

Since every sensation of glare is associated with pain for those affected, surfaces that reflect light well should also be adapted to the work or school environment. The special rules of conduct should also be observed. For example, the person affected should avoid environments with rapidly changing lighting conditions.