Two-dimensional analysis of smooth pursuit eye movements reveals quantitative deficits in precision and accuracy

McIlreavy, Lee ORCID: https://orcid.org/0000-0002-8986-0562, Freeman, Tom C. A. ORCID: https://orcid.org/0000-0002-5989-9183 and Erichsen, Jonathan T. ORCID: https://orcid.org/0000-0003-1545-9853 2019. Two-dimensional analysis of smooth pursuit eye movements reveals quantitative deficits in precision and accuracy. Translational Vision Science & Technology 8 (5) , 7. 10.1167/tvst.8.5.7

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Abstract

Purpose: Small moving targets are followed by pursuit eye movements, with success ubiquitously defined by gain. Gain quantifies accuracy, rather than precision, and only for eye movements along the target trajectory. Analogous to previous studies of fixation, we analyzed pursuit performance in two dimensions as a function of target direction, velocity, and amplitude. As a subsidiary experiment, we compared pursuit performance against that of fixation. Methods: Eye position was recorded from 15 observers during pursuit. The target was a 0.4° dot that moved across a large screen at 8°/s or 16°/s, either horizontally or vertically, through peak-to-peak amplitudes of 8°, 16°, or 32°. Two-dimensional eye velocity was expressed relative to the target, and a bivariate probability density function computed to obtain accuracy and precision. As a comparison, identical metrics were derived from fixation data. Results: For all target directions, eye velocity was less precise along the target trajectory. Eye velocities orthogonal to the target trajectory were more accurate during vertical pursuit than horizontal. Pursuit accuracy and precision along and orthogonal to the target trajectory decreased at the higher target velocity. Accuracy along the target trajectory decreased with smaller target amplitudes. Conclusions: Orthogonal to the target trajectory, pursuit was inaccurate and imprecise. Compared to fixation, pursuit was less precise and less accurate even when following the stimulus that gave the best performance. Translational Relevance: This analytical approach may help the detection of subtle deficits in slow phase eye movements that could be used as biomarkers for disease progression and/or treatment.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Optometry and Vision Sciences Psychology
Additional Information:	This work is licensed under a Creative Commons Attribution 4.0 International License.
Publisher:	Association for Research in Vision and Ophthalmology (ARVO)
ISSN:	2164-2591
Funders:	BBSRC, College of Optometrists UK
Date of First Compliant Deposit:	6 July 2019
Date of Acceptance:	23 June 2019
Last Modified:	04 May 2023 17:58
URI:	https://orca.cardiff.ac.uk/id/eprint/124052

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