LUNEBURG THEORY OF VISUAL GEODESICS IN BINOCULAR SPACE PERCEPTION

To the Editor:  —The recent article by Paul Squires (A. M. A. Arch. Ophth. 56:288-297, 1956) is, we believe, of some interest, but certain points do need clarification.The Luneburg theory was developed to describe only certain aspects of binocular visual experience, those associated with the purely geometric properties of size and location of objects. The use of small point sources of light in an otherwise totally dark room is an experimental design appropriate to the Luneburg theory. Though Squires' use of small black dots in a diffusely illuminated room could certainly represent an important experiment in its own right, it is not an experimental design appropriate to the Luneburg theory. In this instance, extraneous visual clues are introduced which the theory does not attempt to account for—among other things, color and brightness of objects and, especially, the configuration of the room itself. Such a configuration, possessing rich monocular