What is a junctional scotoma?
Junctional scotoma results from a lesion at the junction of the optic nerve and chiasm. It causes an ipsilateral central scotoma and a superior temporal defect in the other eye.
It occurs because some optic nerve fibers from the inferior temporal retina travel forward for a few millimeters in the contralateral nerve when they decussate in the chiasm; they are thus affected by a lesion in that nerve.
