title: Errors in space perception due to accommodative retinal advance.
abstract: Accommodative retinal advance may be defined as the forward shift of the entire retina from contracture of the ciliary muscle in accommodation. The anterior border moves forward 0.5 millimeters at maximum accommodation, with an asymmetrical distoriton of the image of space. It is as though the retinal image is projected on a thin sheet of rubber pulled out on three sides, the fourth being fixed by attachment to the optic nerve. Accommodative retinal advance explains some puzzling errors of space perception described in dozens of papers and monographs, usually attributed to unequal crowding of retinal receptors, or the mystical upper cerebral activity. The horopter error, the alley error, and the Aubert-Foerster phenomenon are discussed. Credit is given to those early experimenters whose theories have been confirmed.
mesh_terms: D000065:Accommodation, Ocular; D006801:Humans; D007088:Illusions / Q000502:physiology*; D009903:Optical Illusions / Q000502:physiology*; D012160:Retina / Q000502:physiology*; D013028:Space Perception