What type of visual field defect would result from a lesion in the optic chiasm?

What type of visual field defect would result from a lesion in the optic chiasm?

A lesion involving complete optic chiasm, which disrupts the axons from the nasal field of both eyes, causes loss of vision of the right half of the right visual field and the left half of the left visual field. This visual field defect is called as bitemporal hemianopia.

What happens if the optic chiasm is damaged?

Damage to the retina or one of the optic nerves before it reaches the chiasm results in a loss of vision that is limited to the eye of origin. In contrast, damage in the region of the optic chiasm—or more centrally—results in specific types of deficits that involve the visual fields of both eyes (Figure 12.8).

What part of the visual field will be lost or compromised if the optic chiasm is damaged?

Damage at site #3: the optic chiasm would be damaged. In this case, the temporal (lateral) portions of the visual field would be lost.

What is Bitemporal Hemianopsia?

Bitemporal hemianopsia (or bitemporal hemianopia) describes the ocular defect that leads to impaired peripheral vision in the outer temporal halves of the visual field of each eye.

What causes bitemporal hemianopia?

A bitemporal hemianopia is almost always caused by damage to the optic chiasm and can occur from the direct or indirect effects of a variety of lesions, including tumors,1 aneurysms,2 and, less frequently, inflammatory and ischemic diseases.

What is the optic chiasm responsible for?

The optic chiasm, or optic chiasma, is the part of the brain where the optic nerves cross and is therefore of primary importance to the visual pathway. It is located at the base of the brain inferior to the hypothalamus, and approximately 10 mm superior to the pituitary gland within the suprasellar cistern.

What is the significance of the optic chiasm?

The optic nerve connects the brain to the eye. To biologists, the optic chiasm is thought to be a turning point in evolution. 1 It is thought that the crossing and uncrossing optic nerve fibers that travel through the optic chiasm developed in such a way to aid in binocular vision and eye-hand coordination.

Why does pressure on the optic chiasm cause loss of peripheral vision?

The optic nerves meet behind the eye at the optic chiasm. Because the optic chiasm sits above the pituitary gland, a large pituitary tumor can push on the optic nerves or chiasm and cause vision loss. Your peripheral vision is typically affected, but you may also lose central vision and color vision.

Why does optic chiasm damage caused bitemporal hemianopia?

When there is compression at optic chiasm, the visual impulse from both nasal retina are affected, leading to inability to view the temporal, or peripheral, vision. This phenomenon is known as bitemporal hemianopsia.

What would be the visual impact of a benign Tumour in the optic chiasm?

When a pituitary tumor pushes the optic chiasm, it causes visual loss in both eyes. In addition to the optic nerve, which brings vision from the eye to the brain, there are also several other nerves near the pituitary gland that travel to the eyes and help them move normally.

What part of brain is optic chiasm in?

What is Quadranopsia?

quadrantanopia. A loss of vision in a quarter of the visual field. The defect is usually bilateral as it is typically caused by a lesion past the optic chiasma.