Image Based Question-66020

Visual field defect in lesion at site as “marked by a bar” as shown in the picture below is seen in the lesion of which among the following ?

A. Lateral geniculate body.

B. Optic nerve.

C. Optic chiasma

D. Optic tract.

Correct Answer » C Explanation

Ans:C. Optic chiasma.

Visual field defect in lesion at site as “marked by a bar” as shown in the picture above represents Bitemporal hemianopia.

Bilateral/Bitemporal hemianopia is a loss of temporal field vision in both eyes. This may be caused by a lesion that affects the centre of the optic chiasma and damages fibres from the nasal halves of the retina as they decussate. It is usually caused by the tumours in the region of sella turcica, pressure by a suprasellar aneurysm or by chronic arachnoiditis Possible causes of this condition include:

• Pituitary tumour
• Craniopharyngioma
• Suprasellar meningioma