Medical Term:

Wernicke reaction

Pronunciation: vern′ik-ĕ

Definition: in hemianopia, a reaction due to damage of the optic tract, consisting in loss of pupillary constriction when the light is directed to the blind side of the retina; pupillary constriction is maintained when light stimulates the normal side. This sign cannot be seen with a bright light because of intraocular scatter onto the seeing half of the retina.

Synonym(s): Wernicke sign