Further Evidence of Change in Position of the Eyeball During Fixation

The general attitude of ophthalmologists heretofore has been to regard monocular and binocular vision as being dependent on a rather fixed peripheral mechanism in which the visual axis, the position and symmetry of the lens and the position of the eyeball in Listing's plane are not considered to change. The graphic illustrations which are used even in the most recent textbooks and periodicals teach this point of view. THE EARLIER CONCEPTS The much discussed and exactly located center of rotation of the eye is still debated by ophthalmologists. On the supposition that such a center exists, Johann Benedict Listing established the plane which bears his name. It is defined as a stationary plane which passes through the center of rotation of the eyes in a vertical transverse position. He concluded that the eyeball in its rotation, irrespective of direction, would have to rotate about an axis within this plane. On