Light information from retinal ganglion cells travels through the optic nerves, optic chiasm (where the nasal fibers decussate), and the optic tracts, before synapsing in the pretectal nuclei of the dorsal midbrain. Both pretectal nuclei receive input from both eyes. Each pretectal nucleus sends axons to both Edinger-Westphal nuclei.
The near-reflex pathway descends from higher cortical centers directly to the Edinger-Westphal nuclei, bypassing the pretectal nuclei in the dorsal midbrain.
Parasympathetic fibers for pupillary constriction travel along the third cranial nerve to the ipsilateral ciliary ganglion within the orbit.
The tonic pupil (also called Adie pupil) results from damage to the ciliary ganglion or short ciliary nerves followed by aberrant reinnervation.
But the ciliary ganglion is distal to the Edinger Westphal nucleus as well as the pretectal nucleus, so shouldn't there be lack of response to both near and light?
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