Cortical Blindness: Causes, Symptoms And Treatment
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 represents a significant difficulty when 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 of these types is cortical blindness which will be talked about throughout this article.
We call cortical blindness, more recently called neurological visual impairment to the alteration or pathology in which a loss of vision occurs in both eyes due to bilateral involvement of the occipital lobes.
The eyes and the nerve pathways that receive visual information function correctly, even the pupils react to nervous stimulation, but said information is not processed in the brain due to the lesions produced in the fibers in which it would generally be produced. So, the subject does not see because his brain does not register 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 a certain confabulation, imagining what could be seen (without being aware that what is described is not a real vision but rather one’s own construction). Likewise, something that usually attracts 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 its new name (neurological visual disability) includes both this and other situations in which there is a partial loss of 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, since some are able not to trip 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 lesions bilaterally in the occipital lobes , not being able to process visual information coming from the visual system. This injury is usually caused by the existence of a stroke 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 craniocerebral trauma that destroys both occipital bones. Intoxications and tumors (the latter, either because they directly affect the occipital or because they generate 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 said lobe or who have it dysfunctional, as in some malformations produced during pregnancy
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 the 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 to this, in cases where there is perception of luminosity it is possible to perform different types of training to strengthen this 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 vision loss it will remain.
The fact of losing vision or not having it can have a harsh 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 it will have on their daily life. Not only on 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 take next. Psychotherapy may also be necessary to treat adaptive and emotional problems.
At a functional level, the use of external aids may be necessary, such as white or support canes for the blind and/or guide dogs. Learning Braille and using adaptive technology also makes life easier for blind people. Likewise, it is necessary to adapt urban elements such as traffic lights, as well as adapt education or different jobs in such a way that your disability does not represent a handicap
In principle there is no solution for cortical blindness, but the research carried out has made it possible to develop mechanisms that stimulate the brain regions responsible for processing visual information. It could be possible to reactivate or make connections between non-lesioned occipital areas that would allow the processing and partial functioning of vision.
