Cortical blindness. Cortical blindness: causes and signs, danger of pathology Treatment of cortical blindness

In the occipital region of the brain there is a special transmitter - the optic nerve, through which signals are transmitted from the retina to. When the optic nerve is damaged in this area, cortical blindness develops. Most often, the disease is irreversible, so you should consult a doctor at the first symptoms of visual impairment.

The occurrence of cortical blindness is caused by damage to a certain area of ​​the brain, namely its occipital part. In this area, on the inner surface along the edges of the calcarine groove, the visual endings end, which come from the periphery. In other parts, a synthesis of visual perception is performed.

The development of the disease in adults may be due to the following factors:

1. Head injury.
2. Sharp increase.
3. Pathological neoplasms in the occipital lobe.
4. Transferred.
5. Progressive multifocal leukoencephalopathy.

Cortical blindness develops only with extensive damage to the occipital region. There is a high probability of developing pathology in diabetes mellitus and against the background of infectious diseases - meningitis, encephalitis.

Cortical blindness can be congenital. Intrauterine hypoxia, infection of the fetus during pregnancy, and toxemia of pregnant women can contribute to the development of pathology. It should be noted that such cases are rare.

How does the disease manifest?

At the beginning of the development of the disease, the patient experiences clouding and blurred vision, and orientation in space is disturbed. It should be noted that with cortical blindness, vision is preserved, but visual orientation is lost. The environment is alien and incomprehensible, which makes a person helpless.

Characteristic signs of pathology are:

• Lack of visual perception.
• Lack of oculomotor function.
• Weak response to movements.

In bright light, a healthy person’s eyelids reflexively begin to close, but with cortical blindness this does not happen.Despite all this, the reaction of the pupil to light is preserved and ophthalmoscopy has normal indicators.

This is due to the fact that the nerve endings from the retina to the brain stem have not lost their functionality.With unilateral damage, visual dysfunction is characteristic, and the patient cannot distinguish colors.

In addition, accompanying symptoms may be observed: alexia, memory impairment, neurological signs, etc.

Symptoms in most cases depend on the degree and location of damage to the cerebral cortex.Visual impairment in children and the development of cortical blindness are often caused by hydrocephalus, epilepsy, and cerebral palsy.

More information about the causes of temporary vision loss can be found in the video:

If cortical blindness is congenital, then the patient’s motor skills and spoken language are delayed in development. Difficulty for the patient at a more mature age is due to the difficulty of adaptation.

The danger of the disease is that there is a high probability of developing vestibulopathy or vestibular disorder. Some deviations occur in the vestibular system, which manifests itself in the form of the following symptoms:

• Balance imbalance.
• Frequent.
• Headache.
• Involuntary eye movement.

A patient with vestibulopathy has difficulty walking and may stagger in different directions. This could cause a person to fall and be seriously injured.

Diagnosis of pathology

When identifying symptoms of cortical blindness, it is important to carry out a differential diagnosis with retinal pathologies and hysteria. It is important to identify the causes of cortical blindness at an early stage.

To study the boundaries of the visual field, 2 methods are used - perimetry and campimetry. To determine the severity of the pathology, a special scale is used and testing is carried out.

To make a final diagnosis, an ophthalmologist prescribes instrumental methods such as:

• Ophthalmoscopy. When examining the fundus of the eye, pathological changes are observed in hypertension. During the examination, swelling of the fundus of the eye, changes in the color of blood vessels, and hemorrhages in certain areas can be observed.
• Visometry. Visometry can be used to determine visual acuity. Blindness is diagnosed if the indicator is less than 0.05 (6/120.20/400). If visual acuity is within 0.1-0.3, then the person is classified as visually impaired.
• CT scan. Thanks to CT, you can determine the condition of the brain and lesions.
• Echoencephalography and electroencephalography are common methods for diagnosing brain diseases. EEG indicators in case of brain contusion have a high amplitude, namely theta waves. Echoencephalography may reveal symptoms of intracranial pressure in patients with visual dysfunction. This is observed in intracranial hypertension and hypertensive encephalopathy.

Features of treatment and prognosis

Treatment of cortical blindness comes down to eliminating the underlying disease that caused visual dysfunction.

There are no specific treatments for cortical blindness. However, there are rehabilitation exercises that stimulate vision in sick people. Special exercises involve the use of certain objects with contrasting colors. At the same time, while performing the exercises, the patient makes certain movements, which improves the recognition process.

Symptomatic therapy is effective only at an early stage. Patients with arterial hypertension should regularly monitor their blood pressure levels.

If the cause of cortical blindness is ischemic encephalopathy, then medications such as Pentoxifylline, Nicergoline, Vinpocetine, etc. are prescribed. Patients with impaired visual function due to diabetes mellitus should receive supportive care.

The appearance of symptoms of cortical blindness in people with traumatic brain injury requires surgical intervention.

The prognosis for the patient is determined by the degree of damage to the occipital region of the brain. In most cases, the patient loses vision. However, there are cases when spontaneous remission occurs.

Possible complications and consequences

Complications of the disease are determined

I am the nature of the pathology that caused the development of the disease. Cortical blindness due to hypertension can cause complications such as hemorrhage in the anterior chamber of the eye.

If a patient is diagnosed with multifocal leukoencephalopathy, the infectious process will spread to other nearby areas. In the future, this can lead to impaired speech and motor function and memory loss.

Prevention of blindness consists of following the following recommendations:

1. Early diagnosis. If the disease is detected in the early stages, it is possible to prevent complete loss of vision.
2. Avoid injury.
3. Treat infectious diseases in a timely manner.
4. People with diabetes need to control their blood sugar levels.
5. Avoid provoking factors.
6. Improve your health (stop smoking and alcohol, exercise, control your body weight, eat right).
7. Visit an ophthalmologist promptly at the first signs of the disease. This will allow treatment to be applied before vision begins to deteriorate.
8. During pregnancy, you should take your health seriously to avoid intrauterine hypoxia and other abnormalities in fetal development, which can cause the development of cortical blindness in combination with neurological symptoms.

If the patient has irreversible blindness, then the necessary conditions should be created, habits should be reorganized and the direction of daily life should be changed. Changing some conditions will make it possible to do the usual things, but only with different methods. There are reading software, visual aids, and special books for the blind. Such measures will help improve the lives of people with blindness.

is a complete lack of vision caused by damage to the occipital lobes of the brain. It manifests itself as a violation of visual perception with intact reaction of the pupils to light. With the congenital variant of the disease, difficulties are observed in the development of speech and motor activity in the child. For diagnosis, visometry, perimetry, ophthalmoscopy, head CT, electroencephalography, echoencephalography are used. Etiotropic therapy is reduced to eliminating the underlying disease. Drug treatment is indicated for malignant hypertension and encephalopathy. Surgery is used for arteriovenous malformations.

General information

Cortical blindness was first described by the Spanish ophthalmologist Marquis in 1934. The prevalence of pathology in the general structure of blindness is 5-7%. In 48% of patients, the etiology of the disease is associated with prenatal damage to the central nervous system. In children under 3 years of age, the most common cause is postgeniculate visual lesions. With encephalopathy, damage to the organ of vision is observed in 15-20% of cases. In 63% of patients, the paroxysmal type occurs, while the permanent type occurs in 37%. Pathology can develop at any age. Men and women get sick with the same frequency. Geographical distribution features have not been described.

Causes of cortical blindness

The disease often occurs sporadically. The development of the congenital form is potentiated by intrauterine hypoxia, toxemia of pregnant women, and brain damage by viral agents when the fetus is infected during pregnancy. The etiology of the acquired form is due to:

• Hypoxic-ischemic encephalopathy. An insufficient number of anastomoses between the cortical branches of the middle and posterior cerebral arteries in the region of the occipital cortex leads to ischemia of this area. Hypoxic changes lead to impairment of central (macular) vision.
• Malignant arterial hypertension. When blood pressure rises above 220/130 mm. rt. Art. swelling of the optic disc occurs with the formation of multiple zones of hemorrhage and exudation in the fundus, however, blindness of central origin can occur only with an increase in the clinical picture of hypertensive encephalopathy.
• Progressive multifocal leukoencephalopathy (PML). PML is a rapidly progressive demyelinating pathology of the central nervous system, in which asymmetric damage to the cortex is observed. This disease often causes the development of hemianopia, less often - complete cortical blindness.
• Arteriovenous malformations (AVM). Against the background of pathological changes in blood vessels, hemorrhages occur in the brain tissue. The organization of a blood clot entails irreversible changes in the affected area. When the bleeding area spreads to the occipital lobe, vision loss occurs.
• Pathological neoplasms. When space-occupying lesions are localized in the occipital lobe, destruction of the neural network occurs with irreversible visual dysfunction.
• Head injury. Cortical blindness develops from traumatic injuries in the visual cortex.
• A sharp increase in intracranial pressure. Intracranial hypertension leads to compression of brain structures and temporary visual dysfunction.

Pathogenesis

Cortical blindness occurs only in the case of total damage to the occipital region of the cerebral cortex. Additionally, Graziole optic radiance may be involved in the pathological process. With unilateral damage to the occipital lobe, a congruent central scotoma appears. Color agnosia is characteristic of an isolated pathology localized in the occipital lobe of the left hemisphere. The function of the macular areas is not impaired. Bilateral damage leads to complete blindness, which is often accompanied by achromatopsia, apraxia of conjugate eye movements. With concomitant damage to the speech centers, dysphasia develops.

Classification

In most cases, cerebral blindness is an acquired pathology. Congenital cases are extremely rare. Clinical classification includes the following forms of the disease:

• Permanent. The most common option. Develops with irreversible damage to brain structures due to hemorrhagic stroke.
• Paroxysmal. This is a reversible blindness that occurs more often at a young age. Occurs against the background of metabolic disorders, hypertensive crisis, hydrocephalus.

Symptoms of cortical blindness

The first manifestations of pathology are the loss of certain areas from the field of view. Patients complain of the appearance of cloudiness, “veils” before the eyes, and impaired orientation in space. Patients cannot direct their gaze towards an object that is located in the peripheral regions. The progression of the pathological process leads to a total impairment of visual perception. Pupillary response to light is preserved because the nerve pathways from the retina to the brainstem are functioning normally. Patients note that when looking at a light source, there is no reflexive closing of the eyelids. Patients react to loud sounds by turning their heads and moving their eyes towards the source of irritation. In children with congenital cortical blindness, a common concomitant manifestation is dysphasia (impaired speech production).

If visual dysfunction is combined with an inability to distinguish colors and shades, this indicates a unilateral lesion. As the disease develops against the background of functional lesions of the cortex, the symptoms regress on their own. Visual acuity is restored after 3-4 days. First, light perception occurs, then object vision occurs, then patients note regeneration of the color perception function. The disease is isolated. In rare cases, concomitant cortical disorders are observed in the form of alexia (inability to understand written text), hemichromatopsia (loss of color sensitivity in one half of the visual field). Patients also complain of memory impairment, unilateral muscle weakness (hemiparesis). With extensive damage to brain tissue, concomitant neurological symptoms are detected.

Complications

The congenital variant of the disease is complicated by a delay in the formation of motor skills and spoken language. When pathology occurs in adulthood, the patient’s adaptation to the social environment is greatly complicated. Patients with cortical blindness are at high risk of developing vestibulopathy. Complications of blindness of cerebral origin are largely determined by the nature of the underlying disease. With the hypertensive etiology of the disease, there is a high probability of hemorrhages in the anterior chamber of the eye or the vitreous body. With multifocal leukoencephalopathy, the spread of infection to nearby areas leads to memory loss, speech impairment, and movement disorders.

Diagnostics

The diagnosis is based on medical history and the results of specific examination methods. Cortical blindness is supported by such anamnestic information as the connection between the first manifestations of the disease and traumatic injuries, brain infections, and increased blood pressure. Instrumental diagnostics is based on:

• Ophthalmoscopy. When examining the fundus, pathological changes are revealed only if the disease is hypertensive. Swelling of the optic disc and local areas of hemorrhage on the inner membrane are visually determined.
• (Echo-EG). With the development of visual dysfunction in individuals with intracranial hypertension or hypertensive encephalopathy, it is possible to diagnose signs of increased intracranial pressure.

Treatment of cortical blindness

Etiotropic therapy is based on eliminating the underlying disease. Symptomatic treatment is effective only in the early stages. All patients with a history of hypertension should have their blood pressure monitored. If the disease is malignant, antihypertensive therapy is indicated. For ischemic encephalopathy, it is advisable to use pentoxifylline, vinpocetine, and nicergoline. Planned surgical intervention is performed for cerebral AVM, as well as for epidural hematoma in patients with traumatic brain injury. Treatment tactics for cortical blindness in patients with multifocal leukoencephalopathy and congenital forms have not been developed.

Prognosis and prevention

The prognosis for life and work ability is determined by the nature of the damage to brain structures. Often visual dysfunction is irreversible, but in some cases spontaneous remission is observed. There are no specific methods of prevention. Nonspecific preventive measures are reduced to the prevention of perinatal pathology and intrauterine hypoxia. Patients suffering from malignant hypertension need to monitor their blood pressure levels daily. The development of visual dysfunction in the absence of objective signs of eye damage requires a detailed examination of the brain structures.

Blindness due to damage to the cortical zones representing the central part of the visual analyzer by an organic pathological process.

• - sharp deterioration of vision in low light conditions, at dusk and at night...

  Directory of diseases

• - the same as the shell form...

  Big Encyclopedic Polytechnic Dictionary

• - A. m., manifested by a violation of oral speech, reading and writing, caused by damage to the cortex of the speech zone of the frontal lobe of the dominant hemisphere of the brain...

  Large medical dictionary

• - A. s. with secondary impairment of expressive speech...

  Large medical dictionary

• - r., caused by damage to the cerebral cortex in the area of ​​the calcarine sulcus...

  Large medical dictionary

• - G., caused by damage to the neurons of the auditory zone of the cerebral cortex...

  Large medical dictionary

• - D., caused by damage to areas of the cerebral cortex associated with the function of muscles involved in articulation; characterized by a disorder in the pronunciation of syllables while maintaining the correct structure of the word...

  Large medical dictionary

• - K.K., in which the posterior part of the lens cortex is affected...

  Large medical dictionary

• - an area of ​​the cerebral cortex that has a specific function...

  Large medical dictionary

• - blindness caused by damage to the visual centers in the cerebral cortex...

  Large medical dictionary

• - C., caused by irritation of motor centers in the region of the anterior central gyrus of the cerebral hemisphere cortex...

  Large medical dictionary

• - see Kozhevnikov epilepsy...

  Large medical dictionary

• - characterized by the presence in the ore-bearing area or ore mass of crusts of altered ore matter, differing in density, color, composition and often concentrically zonal structure...

  Geological encyclopedia

• - Look at the shell form...

  Encyclopedic Dictionary of Metallurgy

• - see Epilepsy...

  Encyclopedic Dictionary of Brockhaus and Euphron

• - in foundry production; same as shell form...

  Great Soviet Encyclopedia

"Cortical blindness" in books

Blindness of instinct