Three-dimensional Hess screen test with binocular dual search coils in a three-field magnetic system

O. Bergamin, D. S. Zee, D. C. Roberts, K. Landau, A. G. Lasker, D. Straumann

Research output: Contribution to journalArticle

Abstract

Purpose. To establish an objective Hess screen test that allows a simultaneous and binocular analysis of all three axes of eye rotation. Methods. In orthotropic and strabismic human subjects, both eyes were recorded with dual scleral search coils in a three-field magnetic system. Before mounting the search coil annuli on the eyes, the voltage offsets of each channel and the relative magnitudes of the three magnetic fields were determined. For calibration, subjects were only required to fix monocularly on a single reference target. During fixation of targets on the Hess screen by the uncovered eye, the three-dimensional eye position of both the occluded and the viewing eye was simultaneously measured. Results. For clinical interpretation, an easy to understand graphical description of the three-dimensional Hess screen test was developed. Positions of orthotropic and strabismic eyes tended to follow Listing's law, which in both eyes allowed the determination of the primary position, that is, the position of gaze from which pure horizontal and pure vertical movements do not lead to an ocular rotation about the line-of-sight. To a first approximation, the location of primary position is a result of the summation of the individual rotation axes of the six extraocular muscles and thus can be used to infer which muscle is paretic. Conclusions. The three-dimensional Hess screen test with binocular dual search coils in a three-field magnetic system is an objective method to assess the ocular alignment in three dimensions with high precision. From these recordings, the clinician can relate deviations of primary position to specific eye muscle palsies.

Original languageEnglish (US)
Pages (from-to)660-667
Number of pages8
JournalInvestigative Ophthalmology and Visual Science
Volume42
Issue number3
StatePublished - 2001

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Fingerprint Dive into the research topics of 'Three-dimensional Hess screen test with binocular dual search coils in a three-field magnetic system'. Together they form a unique fingerprint.

Cite this