The light reflex pathway:
Retina -> optic nerve -> optic tract -> lateral geniculate nucleus -> pretectal nucleus -> Edinger Westphal nucleus -> Ciliary ganglion -> Pupillary constrictor muscle.
The green items above are the only parts of the pathway that present in the brain stem and specifically in the midbrain.
Ciliary ganglion is in the orbit. Lateral geniculate is in the thalamus.
image in public domain