Changing fixation in the transverse plane at eye level and Hering's law of equal innervation

Abstract

Binocular eye movements were recorded photoelectrically while observers looked from one target to a second, located in a different direction and at a different distance. When the two targets were “real” with no accommodation convergence mismatch, there was (a) eye movement which included symmetrical vergence and conjugate saccades or (b) accommodative vergence which is known to occur in J. Müller's stimulus situation. Hering's law concerning equal innervation for vergence and saccadic eye movements holds best in two special situations, one in which accommodation and convergence are dissociated and the stimulus configuration is far from the observer, and another which entails the limiting case for real targets where the near target occludes the far target for one eye.