Cortical blindness: causes, symptoms and treatment

For blindness to occur, it is not necessary for the eyes to malfunction: the failure may be cerebral.

The sense of sight is one of the most developed and most important for human beings. Although it is not impossible to live without this sense (as the many people who live their lives with blindness deserve), its absence is a major difficulty in 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 in this article.

Cortical blindness

We call cortical blindness, more recently denominated neurological visual disabilityThe eyes and the nerve pathways that receive visual information function properly, including pupil reaction to nerve stimulation, but this information is not processed by the brain due to lesions in the fibers in which it generally occurs.

The eyes and the nervous pathways that receive the visual information work correctly, including the pupils reacting to the nervous stimulation, but this information is not processed in the brain due to the lesions produced in the fibers in which it would usually occur. Thus, 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 the visual information, he/she may experience visual hallucinations.

There may also be some confabulation, imagining what could be seen (without being aware that what is described is not a real vision but a construction of one's own). Also, something that often attracts a great deal of attention is the fact that some subjects with cortical blindness are not aware of the loss of vision, presenting anosognosia.

Although strictly speaking cortical blindness would indicate the complete absence of vision, the fact is that its new name (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 blindness may not be perceived externally, as some are able to avoid tripping or bumping into objects due to such remnants of processed information.

It can occur at any age and from a 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.The patient is unable to process the visual information coming from the visual system. This lesion is usually caused by the existence of a stroke in this area or in the vessels that irrigate it.

The presence of anoxia or certain viral and neurological diseases can also lead to cortical blindness. Another etiology may be the suffering of cranioencephalic trauma that destroys both occipitals. Intoxications and tumors (the latter, either because they directly affect the occipital or because they generate compression against the skull wall of this region of the cortex).

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

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 died.

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

The fact of losing vision or not having it can generate 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 going through and the consequences it will have on his/her daily life.What the patient is experiencing and the consequences it will have on his or her daily life. Not only in the patient, but it is also advisable to carry it out on the close environment. It is necessary to provide guidelines and advice on the next steps to be taken. Psychotherapy may also be necessary to treat adaptive and emotional problems.

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

In principle, there is no solution for cortical blindness, but the research carried out has generated the possibility of developing mechanisms that stimulate the brain regions responsible for processing visual information. It could be possible to reactivate or make connections between non-injured areas of the occipital 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 apperance during in utero evolution. Radiology.