Cranial Nerve Exam: Abnormal Examples: Vergence

Light-near dissociation occurs when the pupils don't react to light but constrict with convergence as part of the near reflex. This is what happens in the Argyll-Robertson pupil (usually seen with neurosyphilis) where there is a pretectal lesion affecting the retinomesencephalic afferents controlling the light reflex but sparing the occipitomesencephalic pathways for the near reflex. NeuroLogic Exam has been supported by a grant from the Slice of Life Development Fund at the University of Utah, the Department of Pediatrics and the Office of Education at the University of Nebraska Medical Center. Viewing the video requires installation of the free QuickTime Plug-in