Deficits of the 2nd cranial nerve affect vision but not extraocular movements.
Deficits of the 3rd cranial nerve cause ptosis, outward and downward eye deviation, and pupil dilation.
Deficits of the 4th cranial nerve impair adduction and do not affect the pupil.
Deficits of the 6th cranial nerve cause the eye to be slightly adducted and do not affect the pupil.