We know the corneal reflex (to a tactile stimulus) is propagated via the trigeminal nucleus and then to the motor parts of the blink reflex. How would a flash light stimulus complete the reflex ark?

The corneal reflex is V-VII (respectively afferent and efferent), while the photomotor afferent is the II pair. The center for this last reflex is located in the Edinger-Westphal nucleus in the mesencephalon tegmentum and the projections run with the III cranial nerve fiber, until the ciliary ganglium then they go as short ciliary nerves to the muscle involved in squeezing the pupils.