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Biomedical subjects

H Solomons

Publications and source records attributed to H Solomons.

4 recordsLinked to original sources
PubMed1975

Derivation of the angle of torsion of the eye.

The angle of torsion of the eye, that is the amount by which the eye rotates about its anterio-posterior axis, changes with the direction of the line of fixation. If the eye can be considered as a rigid body under an elaborate system for constraints its motion can be described by the laws of kinematics. The techniques of linear algebra can then be used to derive an explicit relationship between the angles defining the direction of fixation and the angle of torsion of the eye. The angle of torsion can then be expressed as a function of the angle of rotation of the eye and the direction cosines of the axis of rotation. However, under conditions in which Listing's Law holds these angles, are well defined functions of the angles defining the direction of fixation, and so the angle of torsion, in this case, can be expressed as an explicit function of this direction.

Biomechanical Phenomena↗
PubMed1975

Derivation of the space horopter.

The horopter--the locus of those points in space that would stimulate corresponding points on the retinae of the two eyes--has been previously considered to be a plane curve lying in the horizontal plane. The two-dimensional character of this curve arises as a consequence of limiting all considerations to two dimensions only. However, by considering the retina as a two-dimensional surface in 3-space, geometric analysis reveals the horopter to be a non-planar curve: a twisted cubic curve in space. The classical horopter experiments can then be seen to be plotting self-corresponding lines rather than self-corresponding points, and these lines are found to be the chords of this cubic curve. The equations determining the horopter curve in parametric form have been found expressing each point of the curve as a function of the coordinates of the point of fixation.

Eye Movements↗
PubMed1975

Properties of the space horopter.

For general points of fixation the space horopter has been found to be a twisted cubic curve, which, when fixation is in the median plane, degenerates into a conic curve inclined to the plane of fixation. The inclination of the plane of this conic is found to be a function of the angles of torsion of the two eyes. If these angles are zero and fixation is horizontal the space horopter reduces to the Vieth-Müller circle. Previous experimental techniques for plotting the horopter curve do not in fact determine the locus in space of those points that will stimulate corresponding points in the two retinae: they are, locate the position of certain chords of the space horopter. The Hering-Hillebrand deviation coefficient is found theoretically to be a linear function of the fixation distance. This had been shown experimentally by previous workers, but without any satisfactory explanation.

Biomechanical Phenomena↗