The light reflex pathway consisting of the ganglion cell output of the
retina,which synapses with the neurons in the ipsilateral pretectal olivary
The neurons in the pretectal nucleus send crossed and uncrossed fibers
to the neurons in the visceral portion of the Edinger-Westphal nucleus
on both sides.
These neurons form the preganglionic parasympathetic nerves that travel
within the third nerve to synapse in the orbit at the ciliary ganglion.
Postganglionic parasympathetic nerve fibers pass from the ciliary ganglion
to the eye through the short ciliary nerves to innervate the iris sphincter.