2020–2021 BCSC Basic and Clinical Science Course™
6 Pediatric Ophthalmology and Strabismus
Part I: Strabismus
Chapter 4: Motor Physiology
Basic Principles and Terms
While there are several coordinate systems that are useful for mathematical modeling of rotations of the eye, ocular rotations are clinically considered as horizontal rotations about a vertical axis, corresponding to medial and lateral gaze; vertical rotations about a horizontal axis, corresponding to upward and downward gaze; and torsional rotations about the line of sight. If a change in gaze position is broken down into a series of separate rotations about the horizontal and vertical axes, the final torsion of the eye for a given gaze direction could theoretically vary, depending on the sequence in which the rotations are applied. In practice, the final torsion of the eye is always the same for a given gaze direction, regardless of the sequence by which it arrives there (Donder’s law). Listing’s law specifies this relationship by stipulating that the orientation in a given gaze position is equivalent to that which would result from a single rotation around an axis lying in Listing’s plane.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.