<prompt> The characteristic field defect seen in pituitary tumors isHomonymous hemianopiaComplete vision lossBinasal hemianopiaBitemporal hemianopia  <response>: Ans. d Bitemporal hemianopiaRef: Harrisons 19th ed. 198-199Bitemporal hemianopia is usually caused by tumors in the region of the sells turcica, pressure by a suprasellar aneurysm or by chronic arachnoiditis; these press upon the chiasma so that the fibers going to thenasal halves of each retina are destroyed. Tumors of the pituitary body are most common. 