Retinal pigment abiotrophy is a serious inherited eye disease. Pathology is characterized by degeneration and destruction of the receptors responsible for the perception of light. Another name for the disease is retinitis pigmentosa. This is one of the most dangerous ophthalmic diseases. To date, medicine does not have sufficiently effective methods of treating such a pathology. The disease progresses and leads to blindness. Can vision loss be avoided? We will consider this question further.
Causes
The cause of retinitis pigmentosa abiotrophy is a genetic disorder. The disease is transmitted in several ways:
- autosomal dominant;
- autosomal recessive;
- X-linked recessive.
This means that pathology can be inherited in the following ways:
- from one or two sick parents;
- the disease can occur in the second or third generation;
- the disease can occur in men who are in consanguinity with each other.
Retinitis pigmentosa is observed in both sexes. However, men are more likely to be affected by this disease than women. This is due to the fact that pathology is often inherited by a recessive X-linked method.
The direct cause of retinitis pigmentosa is abnormalities in the genes responsible for the nutrition and blood supply of photoreceptors. As a result, these structures of the eye undergo degenerative changes.
Pathogenesis
On the retina are special neurons that are sensitive to light. They are called photoreceptors. There are 2 types of such structures:
- Cones. These receptors are essential for daylight vision, as they are only sensitive to direct light. They are responsible for visual acuity in good lighting conditions. The defeat of these structures leads to blindness even in the daytime.
- Sticks. We need these photoreceptors in order to see and distinguish objects in low light conditions (for example, in the evening and at night). They are more sensitive to light than cones. Damage to the rods worsens twilight vision.
With retinal pigment abiotrophy, dystrophic changes in the rods first occur. They begin from the periphery, and then reach the center of the eye. In the later stages of the disease, cones are affected. First, a person's night vision worsens, and subsequently the patient begins to poorly distinguish objects even during the day. The disease leads to complete blindness.
International Classification of Diseases
According to ICD-10, retinal pigment abiotrophy belongs to the group of diseases combined under the code H35 (Other retinal diseases). The complete pathology code is H35.5. This group includes all hereditary retinal dystrophies, in particular pigment retinitis.
Symptomatology
The first sign of the disease is visual impairment in low light. It becomes difficult for a person to distinguish objects in the evening. This is an early symptom of a pathology that can occur long before pronounced signs of decreased vision.
Very often, patients associate this manifestation with "night blindness" (vitamin deficiency A). However, in this case, this is a consequence of damage to the retinal rods. The patient has severe eye fatigue, headache attacks and a sensation of flashes of light in front of the eyes.
Then the patient worsens lateral vision. This is due to the fact that damage to the rods begins from the periphery. A person sees the world around him as if through a pipe. The more sticks undergo pathological changes, the more narrow the field of view. In this case, the patient's perception of colors worsens.
This stage of pathology can last for decades. First, the patient's peripheral vision decreases slightly. But as the disease progresses, a person can perceive objects only in a small area in the center of the eye.
In the late stage of the disease, cone damage begins. Day vision is also deteriorating sharply. Gradually, a person becomes completely blind.
Retinal pigment abiotrophy of both eyes is often noted. In this case, the first signs of the disease are observed in childhood, and by the age of 20, the patient may lose his vision. If a person affects only one eye or part of the retina, then the disease develops more slowly.
Complications
This pathology is steadily progressing and leads to complete loss of vision. Blindness is the most dangerous consequence of this pathology.
If the first signs of the disease occurred in adulthood, then retinitis pigmentosa can provoke glaucoma and cataracts. In addition, pathology is often complicated by macular degeneration of the retina. This disease, accompanied by atrophy of the macula of the eyes.
Pathology can lead to a malignant tumor (melanoma) of the retina. Such a complication is noted in rare cases, but it is very dangerous. With melanoma, an eye removal operation is necessary.
Forms of the disease
The progression of the pathology largely depends on the type of inheritance of the disease. Ophthalmologists distinguish the following forms of retinitis pigmentosa abiotrophy:
- Autosomal dominant. Such a pathology is characterized by slow progression. However, the disease can be complicated by cataracts.
- Early autosomal recessive. The first signs of the disease appear in childhood. Pathology is rapidly progressing, the patient is rapidly losing vision.
- Late autosomal recessive. Initial symptoms of pathology occur at the age of about 30 years. The disease is accompanied by severe loss of vision, but progresses slowly.
- Linked to the X chromosome. This form of pathology is most difficult. Loss of vision develops very quickly.
Diagnostics
Retinitis pigmentosa is treated by an ophthalmologist. The following examinations are prescribed to the patient:
- Dark Adaptation Test. Using a special device, the sensitivity of the eye to bright and dim light is recorded.
- Field of view measurement. Using the Goldman perimeter, the boundaries of lateral vision are determined.
- Fundus examination. With pathology on the retina, specific deposits, changes in the optic disc and narrowing of blood vessels are noticeable.
- Contrast sensitivity test. The patient is shown cards with letters or numbers of different colors on a black background. With retinitis pigmentosa, the patient usually does not distinguish between blue shades.
- Electroretinography. Using a special device, the functional state of the retina is studied when exposed to light.
Genetic analysis helps establish the ethology of the disease. However, such a test is not carried out in all laboratories. This is a complex and extensive study. Indeed, many genes are responsible for the nutrition and blood supply to the retina. Identification of mutations in each of them is a rather laborious task.
Conservative treatment
Effective methods of treating retinitis pigmentosa abiotrophy have not been developed. It is impossible to stop the process of destruction of photoreceptors. Modern ophthalmology can only slow down the development of the disease.
The patient is prescribed drugs with retinol (vitamin A). This helps to slow down the process of worsening twilight vision.
Conservative treatment of retinitis pigmentosa abiotrophy also includes the use of biogenic stimulants to improve blood supply to the eye tissues. These are drops of "Taufon", "Retinalamin" and a drug for injection into the eye area "Mildronate".
Strengthening the sclera with biomaterial
Currently, Russian scientists have developed Alloplant biomaterial. With retinitis pigmentosa abiotrophy, it is used to restore normal blood supply to the eye tissues. This is a biological tissue that is injected into the eye. As a result, the sclera is strengthened and photoreceptor nutrition is being established. The material is well established and helps to significantly slow down the development of the disease.
Treatment abroad
Patients often ask questions about the treatment of retinitis pigmentosa in Germany. This is one of the countries in which the latest methods of treatment for this disease are used. At the initial stage, detailed genetic diagnostics are carried out in German clinics. It is necessary to identify the type of mutation in each gene. Then, with the help of electroretinography, the degree of damage to the rods and cones is determined.
Depending on the results of the diagnosis, treatment is prescribed. If the disease is not associated with a mutation in the ABCA4 gene, then patients are prescribed high doses of vitamin A. Drug therapy is supplemented with sessions in a pressure chamber filled with oxygen.
Innovative treatments for retinitis pigmentosa abiotrophy are used. If the patient's degree of eye damage reaches the stage of vision loss, then an artificial retina transplant is performed. This graft is a prosthesis pierced by many electrodes. They mimic the photoreceptors of the eye. Electrodes send impulses to the brain through the optic nerve.
Of course, such a prosthesis cannot completely replace a real retina. After all, it contains only thousands of electrodes, while the human eye is equipped with millions of photoreceptors. However, after implantation, a person can distinguish between the contours of objects, as well as bright white and dark tones.
Retinal stem cell gene therapy is performed. This treatment method is still experimental. Scientists suggest that such therapy promotes the regeneration of photoreceptors. However, before treatment it is necessary to conduct a thorough examination of the patient and make a test implantation, since the stem cells are not shown to all patients.
Forecast
The prognosis of the disease is unfavorable. It is impossible to stop pathological changes in the retina. Modern ophthalmology can only slow down the process of vision loss.
As already mentioned, the rate of development of the disease may depend on various causes. Pigmented retinitis, transmitted through the X chromosome, as well as an early autosomal recessive form, is rapidly progressing. If the patient has damage to only one eye or part of the retina, then the pathological process develops slowly.
Prevention
To date, no methods for the prevention of retinitis pigmentosa have been developed. This pathology is hereditary, and modern medicine cannot affect gene disorders. Therefore, it is important to identify the first signs of pathology in time.
If the patient's twilight vision has worsened, then this symptom should not be attributed to vitamin deficiency. This may be a sign of a more dangerous disease. For any visual impairment, an ophthalmologist should be consulted urgently. This will help slow down the development of retinitis pigmentosa.