Homonymous hemianopsia: causes and methods of treatment

The medical term "hemianopsia" refers to a condition in which a blind spot occurs in half the field of view.The field of vision is the area of ​​space that a person sees without moving his eyes or turning his head. The hemianopsia is a two-sided "partial blindness that is, the loss of half the field of vision of each eye.

There are different types of this kind of pathology of visual perception.It is possible to distinguish heteronomous hemianopsia (loss of the opposite half of the fields of vision), there is also a partial, quarter (upper or lower) hemianopia.The "darkening" of both temporal halves of the field is called bitemporal hemianopsia. Falling out of the parts of the visible space from the side of the nose is a binazal hemianopsia. A "blind spot" in the central part of the field of view is called a hemianopic scotoma.

Homonymous hemianopsia is a condition for which the falling out of the same half of the fields of vision is characteristic.It can be both right or both left half: a person can see only one part of the space falling in the field of view (left or right). The border between the visible part and the "blind spot" with homonymous hemianopsia is the central vertical meridian.

Types and Classifications

As already noted, the right-hand and left-handed homonymous hemianopsia are distinguished.

Right-handhomonymous hemianopsia occurs in cases where the left visual tract is damaged.Left-handis caused by a lesion of the right visual tract.

This pathological condition has one more classification. Specialists distinguish:

• Full homonymous hemianopsia.In this case, the "blind spot" fills half of the visible space, reaching the periphery of the field of view.
• Quadrant homonymous hemianopsia:The visual defect occupies only the upper or lower quarter (quadrant).
• Partial homonymous hemianopsia.This means "darkening" of a more local fragment of the field of view.
• Scots, at which the center of the visible space falls out.

Quadrant homonymous hemianopsia can be upper quadrant or lower quadrant, quadrant partial or quadrant complete.

Distinguish also congenital homonymous hemianopsia and developed as a consequence of a number of diseases.

Causes

The appearance of this visual defect is explained by pathology in the visual tract, as well as the cerebral cortex.

Homonymous hemianopsia- this is the consequence of damage to the areas of the brain, in which visual signals should come. Signals of the right and left eyes are transmitted along the optic nerves in such a way that problems in the left hemisphere of the brain cause a "blackout" right half of the field of view in each eye, destructive processes in the right hemisphere - this is the factor causing the fall of the left half of the fields view.

The problem can be explained by congenital pathology. But it can also be caused by various diseases that affect the brain.

The causes of homonymous hemianopsia are most often the consequences of a stroke. But also this condition can be explained by the presence of a tumor, an abscess, an inflammatory process, a trauma or an injury to the head area.

Homonymous hemianopsia is causedan aneurysm of the artery of the base of the brain, circulatory problems in the region of the posterior and middle cerebral arteries, basal meningitis, meningoencephalitis.

All these conditions can cause the development of the inflammatory process, squeezing and impaired blood supply to the optic nerve fiber.Nerve fibers also have a pathogenic effect on toxins.After a while, under the influence of these factors, the visual pathway gradually disintegrates.

Depending on what type of homonymous hemianopsia is found in the patient, the specialist determines in which specific location the lesion is located. For example, the lower-quadrant homonymous hemianopsia develops in the case of problems that have arisen in the parietal lobe of the brain. The disease, localized in the temporal lobe, causes manifestations of a complete upper-quadrant hemianopsia.

Symptoms

Homonymous hemianopsia can sometimes not be noticeable to the patient.On the visual acuity, homonymous hemianopsia has no effect. Defects of vision in some cases are detected only during the field of vision. The manifestations of this type of hemianopsia are the loss of the temporal part of the field of vision on one side, and the nasal part on the other.Sometimes half the field of view disappears completely (complete hemianopsia).In some cases, "blackout" does not reach the periphery of the field of view (incomplete hemianopsia).

There have been cases in which the remaining half of the field of view slightly "overlaps" the blind side.

Homonymous hemianopsia can impede the movement of a person.People, in a number of cases, run into obstacles located on the side of the "fallen out" half of the field of view. It is almost impossible for a patient to drive a car, to distinguish objects that are in the "blind zone" of the table. Defects in sight make reading difficult: the reader can not find a new line of the book. Such states can be unstable.

Sometimes a visual hallucination can become a symptom of homonymous hemianopsia. Especially often this disorder is manifested in cases when the loss of part of the field of vision develops after a stroke.

Possible complications

Depending on a number of factors (the severity of the disease provoking hemianopsia, the duration of the period of occurrence of violations, individual characteristics of the body), a person suffering from hemianopsia can either completely lose sight, or his reestablish.

Diagnostics

Determine the violation can be after studying the state of three important features of the work of the organs of vision:

• visual acuity;
• field of view;
• ophthalmoscopy.

A defect can be detected by examining the fields of vision.The neurological technique includes an indicative check of the fields of vision that the doctor conducts during the examination. To detect smaller problems of visual perception, a specialist can use conventional or computer perimetry.

To diagnose visual field defects in ophthalmology, field-of-view devices are used, (eg, campimetry).Their use makes it possible to investigate the light and color sensitivity of the visual system. Also, devices are used that make it possible to investigate the flicker sensitivity of the visual analyzer.

The doctor can determine the final diagnosis on the basis of obtaining a complete picture of the fundus, as well as concomitant neurologic symptoms.

To determine the exact causes of the onset of visual disturbances, it is important to make an x-ray and CT scan of the brain,The doctor may also prescribe a more complete examination and a series of tests to help diagnose.

Treatment

To get rid of the problems of visual perception, it is necessary to completely eliminate the consequences of diseases that have caused homonymous hemianopsia.If treatment of the underlying disease is not effective and untimely, then hemianopsia can lead to a complete loss of vision.

To eliminate neurological pathologies, surgical treatment, chemotherapy, and medicamental therapy are applied depending on the type and degree of complexity of the underlying problem.

Falling of the fields of vision in hemionopsia

The hemianopsia can not be cured, but after the elimination of the factor causing it, a number of methods can be used that improve the patient's quality of life.For example, a person suffering from homonymous hemianopsia can learn to read, holding the text at an angle of 90 ° and perceiving it vertically.

There are also a number of recommendations that facilitate the movement in space.

Prevention

Prevention of the appearance of such problems with visual perception consists in conducting regular preventive examinations with a neurologist and an ophthalmologist.This will allow time to notice the onset of the development of tumors in the cerebral cortex. Also, the doctor's recommendations and supportive procedures can help to avoid the occurrence of strokes. It is important to prevent the risk of injury to the skull area in every possible way.

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conclusions

Hemianopsia is a defect in the visual perception, in which the loss of half the field of vision develops on every eye. The cause of this condition is the factors associated with damage to areas of the brain, in which visual signals should arrive.

Treatment of hemianopsia is carried out depending on the nature of the underlying disease.

DEmianopsia can be temporary or permanent.This is due to the severity of the visual pathway.

In untimely or poor-quality treatment, pathological processes can lead to a complete loss of vision, and, consequently, to disability.