Ubiquitous gaze

DEFINITION

A phenomenon where the artist positions the eyes of a portrait in such a way that the viewer experiences a sense of being followed by the eyes in the portrait. (I.E. "Mona Lisa" by DaVinci). The same technique is used in Trompe l'Oeil paintings whereas a protruding shelf edge seems to move from side to side with the movement of the viewer. Is it real or is it painted? Source: Eric L. Conklin, Trompe l' Oeil Artist