The two different types of near response are caused by different underlying disease processes. Adie's<unk>  is caused by damage to peripheral pathways to the<unk>  (parasympathetic neurons in the ciliary ganglion that cause<unk> lary constriction to bright light and with near vision). The pathophysiologic mechanism which produces an<unk>  is unclear, but is believed to be the result of bilateral damage to the pretectal nuclei in the midbrain. Studies have failed to demonstrate a focal localising lesion. Research has implicated the rostral midbrain in the vicinity of the cerebral aqueduct of the third ventricle as the most likely region of damage. A lesion in this area would involve efferent<unk> lary fibres on the dorsal aspect of the Edinger-Westphal nucleus (associated with the response to light) while sparing the fibres associated with the response to near, which lie slightly more ventrally. The exact relationship between syphilis and the two types of<unk> s (AR<unk> s and tonic<unk> s) is not known at the present time. The older literature on AR<unk> s did not report the details of<unk> lary constriction (brisk vs. tonic) that are necessary to distinguish AR<unk> s from tonic<unk> s. Tonic<unk> s can occur in neurosyphilis. It is not known whether neurosyphilis itself (infection by Treponema pallidum) can cause tonic<unk> s, or whether tonic<unk> s in syphilis simply reflect a coexisting peripheral neuropathy. Thompson and Kardon summarize the present view: :: The evidence supports a midbrain cause of the AR<unk> , provided one follows Loewenfeld’s definition of the AR<unk>  as small<unk> s that react very poorly to light and yet seem to retain a normal<unk> lary near response that is definitely not tonic. :: To settle the question of whether the AR<unk>  is of central or peripheral origin, it will be necessary to perform iris transillumination (or a magnified slit-lamp examination) in a substantial number of patients who have a<unk> lary light-near dissociation (with and without tonicity of the near reaction), perhaps in many parts of the world. Parinaud syndrome A third cause of light-near dissociation is Parinaud syndrome, also called dorsal midbrain syndrome. This uncommon syndrome involves vertical gaze palsy associated with<unk> s that “accommodate but do not react." The causes of Parinaud syndrome include brain tumors (pinealomas), multiple sclerosis and brainstem infarction. Due to the lack of detail in the older literature and the scarcity of AR<unk> s at the present time, it is not known whether syphilis can cause Parinaud syndrome. It is not known whether AR<unk> s are any different from the<unk> s seen in other dorsal midbrain lesions. The condition is diagnosed clinically by a physician.
Argyll Robertson pupil
Hutchinson's pupil
Blue field entoptic phenomenon
Persistent pupillary membrane
Periorbital dark circles
Emmasofia
Bruns nystagmus
Lipoatrophia semicircularis