Type of visual field defect in lesion at site as “marked by a bar” as shown in the picture below ?
A. Superior quadrantic hemianopia
B. Heteronymous hemianopia
C. Bitemporal hemianopia
D. Homonymous hemianopia
Ans:C. Bitemporal hemianopia
Headache with bitemporal hemianopia with 6/6 vision is seen in Chiasmal lesion.
Central lesions of chiasma
- Bitemporal hemianopia is usually due to chiasmatic disease .
- The most common cause is a pituitary adenoma.
- Other causes are Parasellar or suprasellar lesions such as craniopharyngioma, meningioma, suprasellar aneurysms, glioma of optic chiasma and third ventricular dilatation.
Site of lesion and associated blindness:
|Site of lesion||Features|
|Optic nerve||Complete blindness of the affected eye.|
|Proximal part of optic nerve||
I/L Complete blindness
|Central chiasma||Bitemporal hemianopia|
|Lateral chiasma||Binasal hemianopia|
|Optic tract, geniculate body||Homonymous hemianopia|
|Optic radiation in temporal lobe||Superior quadrantic hemianopia (pie on sky)|
|Optic radiation In parietal lobe||Inferior quadrantic hemianopia (pie on floor)|
|Optic radiation||Homonymous hemianopia|
|Visual cortex sparing macla||Congruous homonymous hemianopia (usually sparing macula)|
|Visual cortex, only macula||Congruous homonymous macular defect|