title: Ocular rotation factor and orientational demand with astigmatic lenses.
abstract: Ocular movements required in most visual functions are affected by lenses in front of the eye. Fundamental to an understanding of these movements are concepts such as the ocular rotation factor and the ocular orientational demand. In this paper the ocular rotation factor for thin spherical lenses is generalized for astigmatic lenses. A compact matrix equation is obtained for the orientational demand in the case of such lenses. The equations are satisfactory in ordinary situations but they break down under certain circumstances. Equations are derived for these special circumstances in particular and also for all circumstances in general.
authors.affiliation: Department of Optometry, Rand Afrikaans University, Auckland Park, South Africa.
authors.forename: W F
authors.initials: WF
authors.lastname: Harris
mesh_terms: D005133:Eye Movements / Q000502:physiology*; D005139:Eyeglasses; D006801:Humans; D008433:Mathematics; D055095:Optics and Photonics; D012399:Rotation