Field defect seen in pituitary adenoma-

Bitemporal hemianopia. Sagittal (central) lesions of the chiasma. These are characterised by bitemporal hemianopia and bitemporal hemianopic paralysis of pupillary reflexes. These usually lead to paial descending optic atrophy. Common causes of central chiasmal lesion are: suprasellar aneurysms, tumours of pituitary gland, craniopharyngioma, suprasellar meningioma and glioma of third ventricle, third ventricular dilatation due to obstructive hydrocephalus and chronic chiasmal arachnoiditis. Ref :AK Khurana 4thE pg 290