Hemianopsia: types, symptoms, causes and treatment

Hemianopsia is one of the neurological alterations that show us to what extent vision is a complex functioning process. Normally we believe that what we see enters through the eyes in the form of light and is represented in the brain as a unit, after our nervous system has been in charge of unifying the information received in format "raw".

However, the sense of sight is based on a process that is not limited to collecting data and joining them, but rather has a much more active role than it seems: it composes images that are not really the same as what is captured by the eyes.

Actually, the simple fact of having a pair of these sensory organs already makes this necessarily the case, and hemianopia helps us understand this. Let's see it.

• Related article: "The 15 most frequent neurological disorders"

What is hemianopsia?

As far as we know, vision is one of the most important senses we have, but it is also true that it can fail in many different ways. Hemianopsia is one of them.

As its name suggests, hemianopsia has to do with the hemispheres, or rather, the hemibodies, which are the sides of our body divided by a vertical axis (ie left or right sides) as far as our nervous system is concerned. Specifically, hemianopsia

is blindness in relation to one side of the visual field.

In other words, it is not that we do not see through one eye and as a consequence our visual field narrows horizontally as one of its sides is reduced; is that in one of the two eyes, or in both, one of the two halves of the visual field has ceased to exist

Symptoms

Hemianopsia may seem unusual and it is not as easy to understand as conventional blindness, but in reality it is still a neurological disease that affects vision. Therefore, all its associated symptoms have to do with this class of problems: orientation problems, confusion due to not finding a space, person or object, feeling of not knowing where you are, etc.

It is also possible that these symptoms are mixed with those of the accident or illness that in turn has caused the hemianopsia, which, as we will see, can be caused by a wide variety of phenomena.

In any case, these symptoms also depend on the type of hemianopsia in question, since this alteration appears in different ways.

Guys

The main types of hemianopsia obey a first fundamental classification: Unilateral and bilateral hemianopsia. In the first case, the alteration only affects one of the eyes, while in the second, it manifests itself in the vision that depends on both eyes.

In turn, bilateral hemianopsia it can be homonymous, if the affected side in both eyes is the same, or heteronymous, if in each eye the affected side is different: in one it affects the right, and in the other, the left.

Causes

Normally, hemianopsia is caused by lesions caused by trauma, stroke, and tumors, all of which structurally affect the nervous system.

However, in some cases it may be due to temporary phenomena such as substance use or migraines with aura, which can generate temporary hemianopsia, with very rapid remission of symptoms.

The parts of the nervous system that are usually behind the hemianopsia are the optic chiasma or the last sections of the optic pathways on their way to the thalamus: the optic tracts.

Difference with hemineglect

It is possible to confuse hemianopsia with hemineglect, a neurological disorder that also has to do with hemibodies.

The main difference between the two is that in hemineglect, it is not only vision that is affected, but the experimentation of all the senses.

The second important difference is that in hemineglect the problem is not technically in vision itself, but rather in attention. Sensory data reaches the brain, but they are not processed as if they were relevant: they are “discarded”. For this reason, it has been seen that there is a kind of very meager notion of what happens in the ignored half of the body, although this information does not pass into consciousness and the person believes that they have not realized anything, as has been seen in experiments.

• You may be interested in: "Hemineglect: patients for whom the left side does not exist"

Treatment

In the case of transient hemianopsia, the intervention is limited to ensuring the well-being of the person until the effects pass. Treatments aimed at intervening in non-transient hemianopsia They're the neurological rehab type., assuming that full recovery may not occur.