On the normal motions of the human eye in relation to binocular vision

Abstract

The Motions of the Human Eye are of considerable interest, as well for the physiology of voluntary muscular motion in general, as for the physiology of vision. Therefore I may he allowed to bring before this Society the results of some investigations relating to them, which I have made myself; and I may venture perhaps to hope that they are such as to interest not only physiologists and medical men, but every scientific man who desires to understand the mechanism of the perceptions of our senses. The eyeball may be considered as a sphere, which can be turned round its centre as a fixed point. Although this description is not absolutely accurate, it is sufficiently so for our present purpose. The eyeball, indeed, is not fixed during its motion by the solid walls of an articular excavation, like the bone of the thigh ; but, although it is surrounded at its posterior surface only by soft cellular tissue and fat, it cannot be moved in a per­ceptible degree forward and backward, because the volume of the cellular tissue, included between the eyeball and the osseous walls of the orbit, cannot be diminished or augmented by forces so feeble as the muscles of the eye are able to exert.