In iris heterochromia, the irises of the two eyes are different colors. In most cases, the phenomenon is due to a congenital anomaly, syndrome, or inflammation and depigmentation thus caused. Many heterochromias do not require treatment because they do not affect vision.
What is iris heterochromia?
Eye color is the pigmentation of the iris, or iris. Normally, the eye colors of both eyes are the same. In people with iris heterochromia, this is not the case. The pigmentation of the skin and the eyes is regulated by the so-called melanocytes. These are cells that synthesize and express melanin. Melanin exists in different shades: dark brown pigment is called eumelanin, for example, while yellowish-red melanin is called pheomelanin. In a healthy person, there is usually a combination of the two types of pigment, the exact composition of which determines the individual skin and eye color. The difference between the two rainbow skins corresponds to a disorder of pigmentation, also called odd-eye, which affects humans rather rarely. White and pied pets such as cats and dogs are more often affected by the phenomenon. As a rule, the pigmentation disorder is depigmentation. Sections of the eye in this case do not contain melanin and thus appear bluish. In addition to congenital forms, iris heterochromia can also be acquired and, in this secondary form, is often the result of iritis.
Causes
Iris heterochromia usually corresponds to depigmentation of the iris and may be a congenital phenomenon. In this case, the phenomenon is mainly associated with Waardenburg syndrome, which is due to a mutational embryonic differentiation disorder in the neural crests. In most cases, Waardenburg syndrome is associated with a deficient emigration of melanocytes leading to pigmentary disorders. In addition to these pigmentary disorders of the iris, sensorineural hearing loss is the main symptom of the mutation-related syndrome. The acquired form of iris depigmentation is usually causally related to iris skin inflammations. Such inflammations occur, for example, in the context of autoimmune diseases such as ankylosing spondylitis, in which the immune system attacks the body’s own tissue. In addition, iritis can correspond to an immunological reaction to infectious diseases. For example, the iris can become inflamed during infections with herpes viruses or Lyme disease, and the inflammation can cause destruction of pigment-synthesizing melanocytes, which later manifests as depigmentation. Less commonly, iris heterochromia is a symptom of a nervus sympathicus defect.
Symptoms, complaints, and signs
Patients with iris heterochromia have different colored eyes. The depigmented eye usually appears paler than the other. Congenital pigmentary disorders of the iris are associated with leucism and may be accompanied by other pigmentary disorders and sensorineural hearing loss as part of Waardenburg syndrome. In acquired iris heterochromia due to iris inflammation, the pigmentary disorder may be accompanied by cataracts and other lens opacities. In many cases, especially those with neurogenic causes, unequal pupil width is present in addition to rainbow skin inequality. Normally, vision is not affected by the pigmentary disorder. Sectorial heterochromia is present when not the entire eye, but only a certain iris segment is color-differentiated, often an iris segment running obliquely to the center. In central heterochromia, a different colored ring is present at the center of the iris. This form of iris heterochromia is common in the population and need not be associated with disease.
Diagnosis and course of the disease
The diagnosis of iris heterochromia is usually made by the physician by gaze diagnosis, since the color difference is immediately obvious. As part of the diagnostic process, the cause of the color difference must be determined in more detail. The main focus is on the estimation of the disease value. In the case of congenital syndromes such as Waardenburg syndrome, a functional test of the auditory system is used for diagnosis. Inflammations are traced by means of laboratory diagnostic analyses.If the cause is inflammatory, the physician must further differentiate between autoimmunologic and infectious triggers during diagnosis to initiate appropriate treatment.
Complications
In most cases, iris heterochromia does not result in any particular complications or symptoms. If iris heterochromia does not lead to limitations in vision or in everyday life in general, treatment is not necessarily required. In many cases, the affected person can see better in one eye than in the other. It is not uncommon for iris heterochromia to lead to the development of hearing loss. Especially in young people, hearing loss can lead to depression and other psychological upsets. Usually, the diagnosis can be made very quickly, since the manifestation of this disease is directly visible to the doctor. Similarly, the hearing is checked, and there are no particular complications. In many cases, no treatment of this disease takes place. Only in case of infections or inflammations a treatment with the help of antibiotics can take place. This usually leads to success and no further complications occur. If there are visual complaints, these can be compensated with the help of glasses. Life expectancy is not reduced or affected by iris heterochromia.
When should you see a doctor?
Normally, iris heterochromia does not require consultation with a doctor. It is a change in eye color, but not health dysfunction. Since vision is not impaired or iris heterochromia does not lead to premature visual disturbances, there is no cause for concern from a medical point of view. A visit to the doctor is only necessary if the abnormalities are seen as an optical blemish and emotional as well as mental problems arise as a result. If there is a depressive experience, feelings of shame or social withdrawal, a visit to the doctor is necessary. A loss of well-being, reduced performance and apathy are symptoms for which a visit to the doctor is recommended. In case of behavioral abnormalities or personality disorders that occur due to iris heterochromia, the affected person needs help. With the support of a doctor or therapist, changes can be achieved that lead to an improvement in the quality of life. However, if decreased vision, blurred vision, or rapid eye fatigue occurs, a visit to the doctor should be made. In case of headache, a feeling of pressure in the eye sockets or inside the head, bleeding of the eye as well as unusual secretion of the eye, there is a disease that must be examined and treated. If the affected person suffers from clouding of the lens, a visit to the doctor is also necessary.
Treatment and therapy
In most cases, iris heterochromia does not affect vision. For this reason, in many cases, no further treatment of the condition is necessary. If patients are bothered by the heterochromia, they are advised to use contact lenses of the required color. If the heterochromia occurs in the context of an acquired disease, causal therapy of the trigger is indicated, such as combating infectious inflammation by administration of antibiotics. In syndromes such as Waardenburg syndrome, causal therapy is not possible because it is a mutation-related disease. Existing symptoms such as sensorineural hearing loss are treated symptomatically. Further therapy of heterochromia is necessary in cases of congenital causes, especially in Fuchs heterochromocyclitis, since inflammation is also involved. In autoimmunologically caused inflammations with heterochromia, for example in the context of multiple sclerosis, an acute flare-up is usually brought to an end with high doses of cortisone. This anti-inflammatory drug can cross the blood–brain barrier and thus penetrate the central nervous system. Patients of autoimmune diseases also receive prophylaxis against relapses with medication to prevent recurrent inflammation.
Outlook and prognosis
Congenital iris heterochromia may not be problematic from a health standpoint, but it may also be associated with other congenital disorders. If it is associated with Waardenburg syndrome, affected individuals additionally suffer from deafness.This disorder is inherited autosomally, but may also be due to other manifestations of leucism. However, since all physical impairments associated with it are congenital, there is no possibility of complete cure. Iris heterochromia due to inflammation of the iris, on the other hand, is a secondary condition indicating that permanent damage has been done to the iris. Over the course of a person’s lifetime, this can develop into cataracts or a form of lens opacity that can ultimately lead to blindness. Until the case actually occurs, vision is not affected by iris heterochromia and vision remains. More rarely, the pupil width of the affected eye is affected and is no longer open or closed to the same degree as in the other eye, which can affect the person’s sense of sight. It is also possible that the affected eye perceives a warmer perspective than the healthy eye. If disturbing changes in vision occur, then they can be treated to restore the normal image, but the iris heterochromia will persist as a result and may continue to be recognized as such by outsiders.
Prevention
Acquired iris heterochromia due to infection can be prevented to some extent by prompt treatment of the causative infectious disease. To the extent that vaccinations are available, they, too, can be characterized as preventive measures. Congenital causes and autoimmune diseases cannot yet be successfully prevented.
Follow-up
In most cases of iris heterochromia, the measures of an aftercare are very limited or are not available to the affected person at all. In this case, the patient should consult a physician at a very early stage and then also initiate treatment to avoid further complications and also further worsening of the symptoms. An early diagnosis of iris heterochromia always has a very positive effect on the further course of the disease. Treatment is not always necessary for iris heterochromia, so that in most cases follow-up care is also completely unnecessary for this disease. Iris heterochromia usually requires the affected person to take antibiotics. It is always necessary to pay attention to a correct dosage and also to a regular intake of the medication. Likewise, the antibiotics should not be taken together with alcohol, as their effect will otherwise be diminished. In case of any ambiguity or questions, always consult a doctor first. As a rule, the disease does not reduce the life expectancy of the affected person and can be cured relatively well. Further measures of aftercare are no longer necessary in this case.
What you can do yourself
Treatment is not necessary in every case of iris heterochromia. As a rule, affected individuals only need to seek treatment if the condition results in decreased visual acuity or other visual complaints. However, self-help options are severely limited for iris heterochromia. The disease itself can be prevented by treating infections and inflammations of the eye quickly and early. The disease can also be counteracted by specific vaccinations, which are given in consultation with the examining physician. Adherence to certain hygiene standards in the event of eye infections is also advisable for those affected. Iris heterochromia is usually treated with the help of antibiotics, so that the affected person does not have to take any further measures. When taking antibiotics, however, attention should be paid to possible interactions with other medications. In case of doubt, a doctor should always be consulted to prevent side effects. Drinking alcohol while taking antibiotics should be strictly avoided. The use of specially colored contact lenses may limit the external appearance of the disease.
