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 many people who live their lives with blindness merit), their absence is an important difficulty when relating to the world, especially if the blindness is not birth but acquired.
There are many types of blindness, with different characteristics and causes. One of these types is cortical blindness , which will be discussed throughout this article.
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Cortical blindness
We call cortical blindness, more recently called 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 nerve pathways that receive the visual information work correctly, even reacting the pupils to nerve stimulation, but this information is not processed cerebrally due to the injuries produced in the fibers in which it would generally occur. A) Yes, the subject does not see because his brain does not record the visual information . It is possible that even if the subject is not able to process the visual information, I may experience visual hallucinations.
There can also be a certain conspiracy, 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 is often called attention is the fact that some subjects with cortical blindness are not aware of the loss of vision, presenting anosognosia.
Although strictly cortical blindness would indicate the complete absence of vision, the truth is that in its new name (neurological visual disability) this and other situations in which there is a partial loss of vision are included. 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 colliding with objects due to said remnants of processed information.
It can occur at any age and for a variety of causes.
Possible causes
The direct cause of cortical blindness is the presence of lesions bilaterally in the occipital lobes , unable to process visual information from the visual system. This injury is usually caused by the existence of a stroke in said area or in the vessels that irrigate it.
The presence of anoxia or the suffering of certain viral and neurological diseases can also lead to cortical blindness. Another etiology can be the suffering of traumatic brain injuries that destroy both occipital. Poisoning and tumors (the latter, either because they directly affect the occipital or because it generates compression against the skull wall 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 dysfunctional, as in some malformations produced during pregnancy .
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Looking for treatment
Cortical blindness does not have specific treatment, since it is the result of the destruction of the cerebral 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, in cases where there is a perception of brightness, it is possible to perform different types of training to strengthen that capacity and use it adaptively in daily life. Depending on the degree of involvement, there may be some improvement in these cases (especially in children, with greater cerebral plasticity), and even a recovery. However, usually when there is complete loss of vision this will remain.
The fact of losing sight or not having it can have a hard impact on the person who suffers it, and psychological intervention may be required. It will be necessary psychoeducation to understand and accept what has happened , what the patient is living and the consequences he will have in his daily life. Not only in the patient, but also it is convenient to do it on the near environment. It is necessary to provide guidelines for action and advice before the next steps. 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 canes or support for the blind and / or guide dogs. The learning of Braille and the use of adapted technology also facilitates the lives of blind people. In addition, it is necessary to adapt urban elements such as traffic lights, as well as adapt education or different employment positions in such a way that their disability does not imply a disability .
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 the processing of visual information. It could be reactivated or made connections between occipital areas not injuries that would allow the processing and partial functioning of the vision.
Bibliographic references:
- Hutto C, Arvin A, Jacobs R, et al. (1987). Intrauterine herpes simplex infection. J Pediatrics 110: 97-101.
- Greene M, Benacerraf B, Crawford J, Hydranencephaly. (2001). Us apperance during in utero evolution. Radiology
