Light–near dissociation can also result from aberrant regeneration of damaged nerves that restores the near reflex but not the light reflex. Misdirected growth can occur after traumatic injury or chronic compression of CN III. Sometimes aberrant regeneration involves the medial rectus fibers and pupillary contraction occurs during attempted adduction. This synkinetic pupil movement can resemble light–near dissociation.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.