The sense of sight is one of the most developed and most important for humans. While it is not impossible to live without this sense (as many people who live their lives with blindness deserve), their absence poses a significant difficulty in 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.
We call cortical blindness, more recently called neurological visual impairment, In 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 are functioning properly, even making the pupils respond to nerve stimulation, but this information fails to be processed in the brain due to the damage produced in the fibers in which it would usually occur. like that, the subject does not see because his brain does not register visual information. It is possible that even if the subject is not able to process visual information, they may have visual hallucinations.
There can also be a conspiracy, imagining what you might see (without realizing that what is described is not a real vision but a construction of your own). Also, something that usually gets a lot of attention is the fact that some subjects with cortical blindness are unaware of vision loss, presenting with anosognosia.
While strictly cortical blindness would indicate a complete absence of vision, the truth is that its new name (neurological visual impairment) includes both this situation and others in which there is partial loss of vision. Although it’s called blindness, in some cases, the subject is able to perceive minimal stimulation, such as light. In some cases, you may not perceive blindness from the outside, as some are unable to trip or collide with objects due to the remaining fingers of the information being processed.
It can occur at any age and for a variety of reasons.
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. This injury is usually caused by the existence of a stroke in this 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 can be the suffering of cranioencephalic trauma which destroys both occipitals. Poisoning and tumors (the latter either because they directly affect the occipital or because they generate compression against the wall of the skull in this region of the cortex).
Finally, cortical blindness can also be observed in subjects who do not have said lobe or who have a dysfunction of it, as in certain malformations produced during pregnancy.
Cortical blindness has no specific treatment because it is the result of the destruction of the parts of the brain that allow visual processing. The exception would be cases in which its cause was a dysfunction of the occipital cortex generated by a treatable cause, such as an infection, as long as the brain tissue is not dead.
In addition to this, in cases where there is a perception of brightness, it is possible to perform different types of training to build this capacity and use it adaptively in everyday life. Depending on the degree of impairment, there may be some improvement in these cases (especially in children, such as greater brain plasticity), or even recovery. However, usually with complete loss of vision, it will stay.
Losing vision or not having it can have a serious impact on the sufferer, psychological intervention may be necessary. Psychoeducation will be necessary to understand and accept what happened, What the patient experiences and the consequences that this will have on his daily life. Not only in the patient, but also convenient to perform it on the surrounding environment. It is necessary to provide guidelines for action and advice on action to be taken below. Psychotherapy may also be needed to treat adaptive and emotional issues.
Functionally, it may be necessary to use external aids, such as white canes or a support for blind and / or guide dogs. Learning Braille and using suitable technology also makes life easier for the blind. It is also necessary to adapt urban elements such as traffic lights adapt education or different jobs so that their disability does not imply a disability.
In principle, there is no solution to cortical blindness, but research has led to the development of mechanisms that stimulate the regions of the brain responsible for processing visual information. It might be possible to reactivate or make connections between areas of the occipital without injury that would allow processing and partial functioning of vision.
- Hutto 100, Arvin A. Jacobs R. et al. (1987). Intrauterine herpes simplex infections. J Pediatrics 110: 97-101.
- Greene M, Benacerraf B, Crawford J, Hydranencephaly. (2001). The emergence of the United States during in utero evolution. Radiology.