In medicine, Leber’s optic atrophy refers to a disease that affects the optic nerves of the eyes. It leads to degeneration of the fibers, resulting in massive limitations of vision and even blindness.
What is Leber’s optic atrophy?
Leber’s optic atrophy is a rare inherited disorder that affects eye health. Despite its slightly misleading name, the condition has nothing to do with the organ Leber: The name comes from its discoverer, ophthalmologist Theodor Carl Gustav von Leber. It affects the optic nerve and is of genetic origin. With a frequency of 1 in 50,000 to 1 in 100,000, Leber’s optic atrophy is rare in the general population. It primarily affects men, who develop the disease between the ages of 15 and 35. The disease rarely breaks out in childhood. There is no established treatment for Leber’s optic atrophy. Therefore, the disease reduces the vision of almost all affected persons to two to five percent. In medicine, Leber’s optic atrophy is classified as a mitochondriopathy. This is a group of diseases whose cause lies in the mitochondria of the body’s own cells.
Causes
Leber optic atrophy is passed from women of one generation to the next. This form of inheritance is what medical science calls maternal (maternal) heritability. Nevertheless, Lebers optic atrophy breaks out much less frequently in the women themselves. A point mutation in the mitochondrial gene sequence is responsible. Mitochondria are special organelles found in every animal cell. Biology also calls them “power plants of the cell” because they are indispensable for cellular respiration in animal (and thus also human) cells. In this biochemical process, the mtochondria produce chemically bound energy (ATP), which the cell can use directly. From a genetic point of view, mitochondria are distinguished from other cell components by a special feature: They have their own genetic information, while the DNA in the cell nucleus stores the genes of other organelles. According to the endosymbiont hypothesis, mitochondria were still independent mini-organisms at an early stage of evolution, at the stage of unicellular organisms. Through symbiosis with other cells, they possibly merged into the larger unicellular organisms, thereby benefiting significantly from the host’s metabolism. Thus, according to the theory, they survived evolutionary selection and are found today only as organelles. However, the mitochondria owe this development to the fact that their genes do not belong to the cell nucleus DNA, but form their own nucleic chains in the mitochondria. In Leber’s optic atrophy, the mutation occurs in this mitochondrial gene sequence. It affects positions 3460, 11778, and 14484. Because only mothers pass their mitochondria to their children, males do not qualify as carriers of this inherited disease.
Symptoms, complaints, and signs
Affected individuals may notice Leber’s optic atrophy at an early stage by impaired color perception: at the beginning, they are less able to distinguish red from green. In the advanced stage, Leber’s optic atrophy also means that sufferers can no longer see sharply in the visual center. Those affected often unconsciously try to compensate for this weakness by looking past the actual object of their interest. As a result, the eye no longer sees that object with the nerves of the visual center, but with the peripheral sensory cells. Since Leber’s optic atrophy does not yet affect the peripheral areas of vision at this point, sufferers can at least partially compensate for the restriction by this seeing past. Another typical feature of Leber’s optic atrophy is that it initially affects only one eye before the symptoms spread to the second eye after some time. There may be a period of up to nine months in between. However, symptoms in the second eye may manifest after only a few days. Furthermore, visual field loss (scotoma) is a potential sign of Leber’s optic atrophy.
Diagnosis and course of the disease
The symptoms described above warrant suspicion of Leber optic atrophy; an optic nerve examination is required for diagnostic workup.An optical procedure can make the background of the eye visible and thus provide more precise information about its condition. Doctors not only have to distinguish where the cause of the symptoms lies; it is also important to distinguish Leber’s optic atrophy from other forms of optic atrophy. Since the disease usually cannot be treated successfully today, those affected must expect a drastic reduction in their vision. Often, only two to five percent of the original ability to see is retained.
Complications
In this disease, those affected suffer primarily from complaints in the eyes. These can manifest themselves in very different ways. As a rule, red-green weakness occurs at the beginning of the disease, so that the affected persons are significantly limited in their everyday life. Furthermore, the disease also leads to a significant reduction in visual acuity, so that patients are usually dependent on glasses or contact lenses. In the worst case, the disease can also lead to complete blindness of the patient, which is also associated with significant restrictions in everyday life. Likewise, the disease also spreads to the other eye and leads to these complaints there as well. Treatment of the blindness is not possible in this case. Not infrequently, there are also failures in the visual field and further disturbances of sensitivity. The treatment of this disease is carried out with the help of medication. Although there are no complications, the symptoms can usually not be completely limited. However, the disease does not affect the patient’s life expectancy, so it is not reduced.
When should you see a doctor?
If vision is impaired, a doctor should be consulted as soon as possible. Changes in vision are considered unusual and should always be medically clarified. If blurred vision occurs and people or objects are no longer recognized as usual, it is advisable to consult a doctor. If there are limitations in spatial vision, there is reason for concern. A doctor should be consulted to ensure that there is no severe or sudden deterioration. If vision is reduced in direct comparison to fellow humans, a check-up should be arranged. If vision continues to decline, the cause of the symptoms should be clarified so that timely treatment can be initiated. If the colors red and green cannot be clearly distinguished from each other, the affected person should discuss the observations with my doctor. If the sufferer notices that he increasingly looks past the targeted objects in order to recognize their contours more clearly, a visit to the doctor is necessary. If the visual acuity is different in both eyes, this should be examined and tested more closely by a doctor. If headaches, dizziness or a feeling of pressure in the head occur, a medical consultation is advisable. In case of a diffuse feeling of illness, pain of the eyes as well as eye socket or an increased risk of accidents, a doctor should be consulted.
Treatment and therapy
Besides some experimental therapeutic approaches, there is no known effective treatment for Leber optic atrophy. However, physicians hope that abstaining from prussic acid will yield initial results. Prussic acid is suspected to be associated with the onset of Leber’s optic atrophy; however, this treatment method does not guarantee success and ideally only supports a positive development of the disease. Prussic acid is found, for example, in alcohol, tobacco, nuts and cabbage. Since 2015, pharmaceutical retailers have also been carrying the first drug containing the active ingredient Idebenone. Researchers originally developed this drug to treat cognitive impairment, such as that seen in Alzheimer’s dementia.
Outlook and prognosis
The prognosis of the disease is unfavorable. It is a genetic disease of Leber optic atrophy. Because, for legal reasons, researchers and scientists are not allowed to alter human genetics, only symptomatic treatment measures can be taken. These are very difficult in this health disorder. Since the disease leads to a weakening of vision, the burden for the affected person in everyday life is very high.This leads to impairments, an increased risk of accidents, and increased risks of secondary diseases. Psychological disorders are often documented in the further course. These must be taken into account in the overall prognosis. In an advanced stage, vision is reduced to such an extent that the fulfillment of daily obligations is no longer possible without the help of other people. In addition, facial deficits occur, leading to a further deterioration of the quality of life. A visual blemish is perceived, which can also become an emotional burden for the affected person. Often the joy of life and the participation in social and community life decreases. In a very unfavorable course of the disease, blindness of both eyes occurs. To improve one’s own health, the affected person should pay sufficient attention to an emotional well-being. Although no cure will occur, coping with the disorder should be learned.
Prevention
Prevention of Leber’s optic atrophy is not possible because it is a hereditary disease. External influences play only a minor role, if any. The measures mentioned above, such as avoiding foods and stimulants containing hydrocyanic acid, can possibly delay an onset or promote a milder course at an early stage.
Follow-up
There are usually few measures of aftercare available to the affected person for this disease, as it cannot be completely cured. If complete blindness of the affected person has occurred, no follow-up care can be provided, as it is usually not necessary either. The disease itself can be treated in some cases with the help of medication. Here, the affected person must pay attention to regular use and also to the correct dosage in order to alleviate the discomfort in the eyes. Likewise, a healthy lifestyle with a healthy diet can have a very positive effect on the further course of the disease and slow down its progression. In particular, the patient should avoid tobacco and alcohol. Since the disease often occurs together with dementia, many of those affected are also dependent on the help and support of their own family in their daily lives. Here, loving and intensive conversations also have a positive effect on the further course of the disease and can also prevent depression or psychological upsets. In most cases, the disease does not reduce the life expectancy of the affected person.
What you can do yourself
Patients with Leber’s optic atrophy experience increasingly severe limitations in their vision due to the disease, and thus in their quality of life. Since the disease first negatively affects the perception of colors, this represents an important symptom for early detection, and those affected immediately consult an ophthalmologist. Patients take the medicines prescribed by a doctor according to the instructions and consult a doctor immediately in case of side effects. As the disease usually progresses, patients come to terms with the increasing impairment of their visual function. The blurred vision can only be compensated for to a certain extent by visual aids such as glasses. Thus, it is most important that those affected accept the disease and try to still achieve a comparatively high quality of life. For example, it is helpful to seek contact with other visually impaired people in order to experience social support. Medical experience so far indicates a negative influence of hydrocyanic acid on the onset and course of the disease. Therefore, patients strictly refrain from the consumption of alcohol or tobacco. In some cases, the disease eventually leads to blindness, so patients adapt their living space to the changed circumstances and learn to orient themselves with a long cane.