Cortical blindness: causes, symptoms and treatment

The sense of sight is one of the most developed and most important for the human being. Although it is not impossible to live without this sense (as the many people who live their lives with blindness deserve), its absence supposes a significant difficulty when it comes to relating to the world, especially if the blindness is not from birth but acquired.

There are many types of blindness, with different characteristics and causes. One such type is cortical blindness., which will be discussed throughout this article.

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cortical blindness

We call cortical blindness, more recently termed neurological visual impairment, to the alteration or pathology in which there is a loss of vision in both eyes due to bilateral involvement of the occipital lobes.

The eyes and the nerve pathways that receive visual information function correctly, including the pupils reacting to stimulation nervous system, but said information is not processed in the brain due to the lesions produced in the fibers in which it is generally transmitted. would produce. So,

the subject does not see because his brain does not register the visual information. It is possible that although the subject is not able to process visual information, he may experience visual hallucinations.

There may also be some conspiracy, imagining what could be seen (without being aware that what is being described is not a real vision but one's own construction). Likewise, something that usually draws a lot of attention is the fact that some subjects with cortical blindness are not aware of the loss of vision, presenting anosognosia.

Although cortical blindness would strictly indicate the complete absence of vision, the truth is that in its new denomination (neurological visual impairment) includes both this and other situations in which there is a loss of partial vision. Although it is called blindness, in some cases the subject is able to perceive some minimal stimulation, such as light. It is possible that in some cases the blindness may not be perceived externally, since some are able not to stumble or collide with objects due to said remnants of processed information.

It can occur at any age and for a wide variety of causes.

Possible causes

The direct cause of cortical blindness is the presence of bilateral lesions in the occipital lobes, unable to process visual information from the visual system. Said lesion is usually caused by the existence of a cerebrovascular accident in said area or in the vessels that supply it.

The presence of anoxia or suffering from certain viral and neurological diseases can also lead to cortical blindness. Another etiology may be suffering from head injuries that destroy both occipitals. Poisoning and tumors (the latter, either because they directly affect the occiput or because it generates compression against the wall of the skull of said region of the cortex).

Finally, cortical blindness can also be observed in subjects who do not have such a lobe or who have it dysfunctionally, as in some malformations produced during pregnancy.

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seeking treatment

Cortical blindness has no specific treatment, since it is the result of the destruction of the brain elements that allow visual processing. The exception would be those cases in which its cause was a dysfunction of the occipital cortex. generated by some treatable cause, such as an infection, as long as the brain tissue has not dead.

In addition to this, in cases where there is a perception of luminosity, it is possible to perform different types of training to strengthen said capacity and use it adaptively in daily life. Depending on the degree of involvement, there could be some improvement in these cases (especially in children, with greater brain plasticity), and even recovery. However, usually when there is complete loss of vision it will remain.

The fact of losing vision or not having it can have a hard impact on the person who suffers from it, and psychological intervention may be required. Psychoeducation will be necessary to understand and accept what has happened, what the patient is experiencing and the consequences that it will have in his daily life. Not only in the patient, but it is also convenient to perform it on the nearby environment. It is necessary to provide guidelines for action and advice regarding the steps to be taken next. Psychotherapy may also be necessary to treat adaptive and emotional problems.

At a functional level, it may be necessary to use external aids, such as white or support canes for the blind and/or guide dogs. Learning Braille and the use of adapted technology also makes life easier for blind people. Likewise, it is necessary to adapt urban elements such as traffic lights, as well as adjust education or different jobs in such a way that your disability does not result in a handicap.

In principle there is no solution for cortical blindness, but the research carried out has generated that it is possible the elaboration of mechanisms that stimulate the brain regions in charge of information processing visual. It could be possible to reactivate or make connections between areas of the occipital non-lesions that would allow the processing and partial functioning of vision.

Bibliographic references:

• Hutto C, Arvin A, Jacobs R, et al. (1987). Intrauterine herpes simplex infections. J Pediatrics 110:97-101.
• Greene M, Benacerraf B, Crawford J, Hydranencephaly. (2001). Us appearance during in utero evolution. Radiology.