Vertical Diplopia

Double vision when looking the affected eye is looking down and in like when reading a newspaper or going down stairs.

This is caused from a lesion to cranial nerve IV (Trochlear)

Lesions to cranial nerve VI (abducens) can cause horizontal diplopia and estropia (inward deviation). Muscles affected = lateral rectus

Lesions to CN III (occulomotor) can cause vertical and horizontal diplopia, ptosis, enlarged and non-reactive pupil. Muscles = superior rectus, medial rectus, inferior rectus and inferior oblique