Diseases of the visual apparatus always give patients a lot of inconvenience and problems. The eyes are the main organ of the senses. With it, a person can see the world around him and fully navigate in space. The most terrible pathology is the loss of central vision. In medical practice, it is found under the name Leber amaurosis. Treatment, symptoms, causes of the disease are just some of the issues that have been discussed in today's article.
Description of the disease and its variants
Amaurosis is a pathology of the ocular apparatus, in which partial or complete blindness is observed. This condition is not associated with direct damage to the organs of vision. It is functional in nature. And the disease is caused by a violation of the nerves of the visual apparatus. This is just the case when during an ophthalmological examination the doctor does not see significant deviations. In this case, the patient complains of persistent visual impairment.
Amaurosis is of two types: transient (transient) and congenital. The first case is characterized by temporary loss of vision. The development of the disease, as a rule, is caused by ischemia in the carotid artery basin. With the help of drug therapy or on their own, vision is soon restored. If symptoms of ischemia progress against a background of transient blindness, surgery is performed. This kind of operation often helps prevent a patient’s stroke.
Leber's congenital amaurosis is of particular interest to doctors and scientists. Therefore, it is advisable to consider this pathology separately.
Features of congenital Leber's amaurosis
Doctors associate the hereditary form of the disease with genetic disorders of rhodopsin production. It is he who is responsible for the transmission of information through nerve bundles to parts of the brain. If rhodopsin is enough, the retina successfully transforms light into impulses, from which visual images are subsequently formed. According to recent studies on this issue, in addition to rhodopsin, the pathological process also extends to other areas - rods and cones.
The first congenital amaurosis of Leber was mentioned in 1867. The scientist, whose name was subsequently named the disease, identified its main manifestations. This is primarily blindness, nystagmus and the appearance of age spots on the fundus. Pathology is quite rare (3 cases for every 100 thousand people). It equally affects both men and the fair sex.
Main reasons
Why does Leber's congenital amaurosis occur? The causes of the disease are still unknown. Many doctors talk about its connection with the lack of a clear specificity of the elements of the pigment epithelium (rhodopsin) with photoreceptors. This is due to abnormalities of the gene material. Pathology has an autosomal recessive mode of transmission. It should be feared only if both parents have a mutating gene in their DNA.
This is the RPE-65 gene on the first chromosome. To date, scientists know about 80 varieties of its mutations that provoke a number of forms of retinal abiotrophy. The protein encoded by this gene is responsible for the metabolism of retinol in the pigment epithelium. In the presence of a genetic defect, the described process fails. As a result, the synthesis of rhodopsin is stopped, which entails the appearance of symptoms characteristic of the disease.
Clinical picture
Leber's hereditary amaurosis is detected already in early childhood. Children with this diagnosis usually have no visual reflexes. They are clumsy and periodically injure themselves. It is worth noting that blindness is not absolute at birth. During the life of the child, it progresses, and closer to puberty, it leads to complete loss of vision. However, there are exceptions.
Leber's congenital amaurosis is characterized by the following symptoms:
- Involuntary eye movements.
- Pupils react poorly to light.
- It is difficult for a child to focus his eyes on one object. He practically does not distinguish nearby objects.
- The gaze constantly wanders.
- Pathology is often accompanied by keratoconus. This is a defect in which the cornea changes its familiar configuration. It becomes conical.
In most cases, Leber's amaurosis is systemic in nature and is associated with other disorders. These children have a lag in mental development. They usually have poor or no hearing. The disease is supplemented by other pathologies of the internal organs.
Diagnostic Methods
Due to the large number of manifestations of the disease from various systems, it is sometimes difficult to suspect Leber's congenital amaurosis in a timely manner. The causes and symptoms of this pathology are not familiar to most parents. Therefore, they do not immediately seek help from a doctor.
An optometrist is involved in the diagnosis. Sometimes the help of outside specialists is required: a neurologist, angiologist, etc. The examination of the patient begins with a study of his medical history. In this case, the doctor may ask clarifying questions during the examination. For example, when the first symptoms of the disease appeared, were there cases of amaurosis in other family members?
Without fail, in a small patient, a specialist examines the fundus, checks vision, the quality of the visual reflex. If necessary, he is sent for an MRI, as well as appoint an additional consultation with a geneticist.
Therapy Features
Leber's amaurosis is not treatable. Appropriate, according to some ophthalmologists, is the appointment of maintenance therapy. This course includes the use of vitamin complexes, intraocular injections and vasodilator drugs.
Usually, for such patients, provided that a sufficient level of vision is maintained, the doctor prescribes glasses. However, even with their help it is very difficult to distinguish facial expressions of others. The child is required to be registered with a neurologist.
Parents, in turn, must clarify the distance at which the baby is able to distinguish the facial expressions of surrounding people. For the correct formation of the central nervous system, it is better for them to be within the given distance limits. This approach will allow the child to recognize faces, copy facial expressions and contact with the next of kin.
Prognosis for patients
Today, doctors cannot offer a focused and at the same time effective way to combat amaurosis. However, around the world, scientists continue to conduct clinical trials and seek a universal cure. Some of them show good results. For example, when the RPE65 gene is introduced into the retina of the eyes, a significant improvement in vision is observed in patients.
As for the prognosis of pathology, it is in most cases unfavorable. In approximately 95% of patients, complete vision loss occurs by 10 years.