Bitemporal hemianopsia is the medical description of a type of partial blindness that is associated with lesions of the optic chiasm, the area where the optic nerves from the right and left eyes cross near the pituitary gland.

The absence of vision in half of a visual field is described as hemianopsia.

The visual field of each eye can be divided in two vertically, with the outer half being described as temporal, and the inner half being described as nasal.

In bitemporal hemianopsia vision is missing in the outer half of both the right and left visual fields. Pituitary adenomata are associated with this kind of visual deficit, as are certain injuries.

Bitemporal hemianopsia can be broken down as follows:

• bi-: involves both left and right visual fields
• temporal: involves the temporal visual field
• hemi-: involves half of each visual field
• anopsia: blindness