Final answer:
The optic chiasm is the branch of the visual pathway where fibers from the medial retinae cross over to the opposite side, facilitating the processing of the visual field by the contralateral side of the brain.
Step-by-step explanation:
The branch of the visual pathway that crosses over to project to the contra lateral side of the brain and is thus associated with the visual system is the optic chiasm (b). At the optic chiasm, fibers from the medial retinae (or nasal halves) of both eyes decussate or cross over to the opposite side. This arrangement allows for the processing of the two halves of the visual field by opposite sides of the brain. When there are deficits in visual field perception, it can indicate damage along the optic pathway between the orbit and the diencephalon, particularly if a pituitary tumor is pressing on the optic chiasm.