Hemianopsia

As hemianopia or hemianopia (from the Greek hemi "half", a " not " and ops "see" - Synonym: Half page blindness) is a frequently called by the vertical centerline limited, unilateral visual field loss, which is usually bilateral, but rarely only one side occurs.

A distinction is two-sided failure

• Homonymous hemianopia (right or left): In both eyes the same side of the failure is affected ( patients seen for example only the left or right side of an image section )

• Heteronymous (typically bitemporal ) hemianopia: In both eyes, the other side is always affected by the failure. ( Patients suffer, for example, by a " tunnel vision " ) This occurs with damage to the optic chiasm and is then usually bitemporal if something presses from the center to the two nerves. A bilateral external compression can lead to binasalen hemianopia, but is very rare and not yet symmetrical, as shown in the picture, has been observed.

Cause is a lesion in the course of the visual pathway. The type of hemianopia allows one to deduce the location of the fault. Is this just before the optic chiasm, the visual field loss may occur on one side, otherwise both sides. Your designation has been made on the direction of visual field loss. A temporal (lateral ) visual field defect for example, therefore, means the failure of the nasal ( facing the nose) half retina of the eye, because the localization of nasal retinal areas is based on temporal and vice versa. Approximately 10% of hemianopia affecting only upper or lower quadrant of the visual field. In addition, hemianopia may be associated with a central macular recess. Their detection is usually due to the small size ( about 1 ° ) while difficult, its importance for the identification occipital causes considerable.

Delimit From the hemianopia is the visual neglect in which a disturbance of allocation of attention to a page exists. Affected patients suffer from this form of Neglects usually due to damage to the brain of the opposite side. The visual pathway must be not directly affected by the lesion.