Bitemporal hemianopia is seen in -

Ans. is 'a' i.e., Pituitary' tumor [Ref: Khurana 4th/ep. 290}o Characteristic visual field defect of central chiasmatic lesion is bitemporal hemianopia. Pituitary tumor causes central chiasmatic lesion.o Bitemporal hemianopia results due to central (sagittal) lesion of the optic chiasma, common causes of which are tumors ofthe pituitary gland (most common), craniopharyngioma, suprasellar meningioma, glioma of third ventricle; chiasmal arachnoiditis, and third ventricular dilatation,Site of lesionVisual field defectOptic nerveBlindnessOptic cbiasmaBitemporal hemianopiaOptic tractIncongruent homonymous hemianopiaLateral geniculate bodyHomonymous hemianopiaOptic radiation (Total)Homonymous hemianopia, sometimes with macular sparingOptic radiation lower fibres (temporal lobe)Homonymous upper quadrantanopiaOptic radiation upper fibres (parietal lobe)Homonymous lower quadrantanopiaVisual cortex (anterior occipital cortex)Homonymous hemianopia with macular sparingOccipital cortex tipHomonymous macular defect