It is a visual disorder in which half the visual field is affected and the person can see only half of the things.
Hemianopsia is a term that originated from three different Greek terms; “Hemi” means half, “an” which means sin and “opsia” which translates into vision. So, basically it means no average vision.
Sometimes, when a person suffers from severe migraine, they may experience temporary hemianopsia, but it is usually short-lived.
While the person suffering from permanent hemianopsia experiences blindness in the middle of their visual field permanently, this is usually due to a brain tumor brain injury.
Patients who suffer from hemianopsia tend to trip over things and are surprised and easily agitated by the sudden appearance of things and people in their field of vision, or so it seems.
They stumble or fall very easily and, therefore, are quite nervous of the crowds and public gatherings.
Types of hemianopsia
Hemianopsia can be of various types depending on which side of the visual field is being lost. It is classified into the following types:
Homonymous hemianopsia : Homonymous hemianopsia is a condition in which the same side of the visual field is lost in both eyes. It can be on the left or right side depending on which side of the brain is affected.
The connection of our brain with the rest of the body is intertwined. Then, the left optic tract on the left side of the brain controls the right side of the vision in both eyes.
Similarly, the right optic tract on the right side of the brain controls the left side of the vision of both eyes. Then, any side of the brain that is affected results in the loss of vision from the opposite sides of both eyes.
Hemianopsia heterónima: It is a type of hemianopsia that can be described as the loss of vision in different visual fields of the eyes.
Binasal hemianopsia: When blindness occurs in the field of vision closest to the nasal part of both eyes, it is called binasal hemianopsia.
This occurs due to the presence of lesions or damage to the lateral retinal nerve fibers that do not cross in the optic chiasm and transmit information from the temporal retina. This results in the loss of vision of the nasal side of both eyes.
Bitemporal hemianopsia: It is the blindness or loss of vision from the external side. This usually occurs due to the formation of lesions or damage to the area of the optic chiasm.
The optic chiasm is actually the area near the pituitary gland where the nerves of both eyes intersect to reach the opposite side of the brain.
Quadrantanopia: It is a loss of vision in a quadrant or quarter of the visual field. The fourth part of vision that is lost due to blindness usually depends on which part of the brain was damaged. Vision loss occurs in the part that is connected to the damaged part of the brain.
Upper hemianopsia: When the loss of vision occurs in the upper part of the visual field of both eyes, it is called superior hemianopsia.
Lower Hemianopsia: If vision loss occurs in the lower half of the eye’s field of vision, then it is called inferior hemianopsia.
As mentioned earlier, hemianopsia can occur due to a severe migraine, but that is only temporary. Other causes of permanent hemianopsia include:
Brain damage: This may be due to an accident or brain surgery that causes injury or damage to some part of the brain that results in hemianopsia. The formation of lesions in different parts of the brain can also be a cause of hemianopsia.
Stroke: When the brain is not getting enough oxygen, it stops working properly, which results in a stroke that is a serious and dangerous medical condition that in most cases, causes death.
But if the patient survives he suffers from several disorders, one of them is hemianopsia.
Brain tumor: The brain tumor can also be a cause of hemianopsia. The formation of tumors in the brain can cause the brain to be damaged or adversely affected, resulting in hemianopsia.
Different techniques to treat patients suffering from hemianopsia are available today. All of them focus on improving a person’s perception and, to a certain extent, their field of vision. But none of them can cure the disorder.
Doctors may choose to apply any of these techniques to treat hemianopsia and sometimes even combine several treatments to achieve better results. Some of them are the following:
Audio visual stimulation training: This is a program designed to improve the condition of the patient with hemianopsia using sound and light.
In this treatment technique, both the affected and the unaffected field of vision of the person suffering from hemianopsia are stimulated using a multisensory approach. It is an especially effective treatment for homonymous hemianopsia.
Exploratory saccadic movements: It is also called scanning therapy. In this treatment therapy, patients suffering from hemianopsia are trained to perform exploratory saccades in that part of the visual field where their vision is lost, without moving the head.
Hemianopsia patients are trained to use this technique in their daily lives.
Optical visual extension expanders: There are some special types of spectacles in which a prism is mounted to increase the visual fields of patients with hemianopsia.
The patient suffering from hemianopsia combines the image provided by the prism with what he can actually see, which increases his field of vision.
Visual restoration therapy
It occurs in half-hour sessions where the patient suffering from hemianopsia fixes his gaze on a point and then has to move his head every time there is a light stimulus in his field of vision.
The computer records the data and after a while the doctor adjusts the technique according to the data provided by the computer.
These were some of the techniques that can be used to better rehabilitate hemianopsia patients and help them live a normal life as possible.