=====Chiasmal syndrome=====
Chiasmal syndrome is the set of signs and symptoms that are associated with lesions of the [[optic chiasm]], manifesting as various impairments of the sufferer's [[visual field]] according to the location of the lesion along the optic nerve. [[pituitary neuroendocrine tumor]]s are the most common cause; however, chiasmal syndrome may be caused by cancer, or associated with other medical conditions such as [[multiple sclerosis]] and [[neurofibromatosis]].