“Indirect” type: blow to the ipsilateral brow (lateral forehead) that deforms the bone and bruises the optic nerve in the optic canal
“Direct” type: penetrating injury to the orbit that makes direct contact with the optic nerve
Blunt trauma to the eye can also cause traumatic optic neuropathy, but vision loss is usually from choroidal rupture or retinal contusion (“commotio retinae”)