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Comparative Study
. 2024 Oct-Dec;17(4):100517.
doi: 10.1016/j.optom.2024.100517. Epub 2024 Jun 21.

Comparison of two visual-verbal tests of ocular motility using an eye-tracker

Carmen López-de-la-Fuente  1 , Elena Saz-Onrubia  2 , Elvira Orduna-Hospital  2 , Ana Sánchez-Cano  2
Affiliations
Comparative Study

Comparison of two visual-verbal tests of ocular motility using an eye-tracker

Carmen López-de-la-Fuente et al. J Optom. 2024 Oct-Dec.

Abstract

Purpose: This study aims to compare eye movements monitored with an eye tracker during two visuo-verbal tests for assessing ocular motility. The study explores the potential of digital assessment and eye tracking technology in enhancing the understanding of ocular motility during these tests.

Methods: 47 healthy participants were included (20 males, 27 females), with a mean age of 21.34±1.77 years. The participants underwent optometric examinations to ensure visual health and exclude any dysfunctions or pathologies. The experimental protocol involved the digitized versions of the DEM and King-Devick tests, monitored with an eye tracker.

Results: The vertical subtests of DEM test showed fewer saccades, longer fixation durations, smaller saccade amplitudes, and slower saccade speeds compared to the horizontal subtest. The King-Devick test exhibited comparable fixation and saccade numbers, while fixation duration slightly increased with test difficulty. Statistically significant differences were found between the tests, but a positive correlation was observed.

Conclusions: Statistically significant differences were observed between the DEM and King-Devick tests, indicating that they measure similar aspects but are not interchangeable. The DEM test offers more comprehensive information with vertical saccade assessment. Test duration correlates positively with saccade and fixation count, fixation duration, and saccade speed.

Keywords: Developmental eye movement test; Eye tracker; Fixations; King-Devick test; Ocular motility; Saccades.

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Conflict of interest statement

Conflicts of interest None.

Figures

Fig 1
Fig. 1
(a) Scatter diagram with regression line of duration of subtest C in the DEM test by number of fixations of each participant. (b) Scatter diagram with regression line of duration of subtest C in the DEM test by duration of fixations. (c) Scatter diagram with regression line of duration of subtest C in the DEM test by number of saccades. (d) Scatter diagram with regression line of duration of subtest C in the DEM test by saccadic speed.
Fig 2
Fig. 2
(a) Scatter diagram with regression line of duration of the combined subtests II and III of the KD by number of fixations of each participant- (b) Scatter diagram with regression line of duration of the combined subtests II and III of the KD by duration of fixations. (c) Scatter diagram with regression line of duration of the combined subtests II and III of the KD by number of saccades. (d) Scatter diagram with regression line of duration of the combined subtests II and III of the KD by saccadic speed.
Fig 3
Fig. 3
Bland-Altman plots illustrating the agreement between the KD and DEM tests across various parameters. The plots depict the duration of test completion (a), number and duration of fixations (b) (d), number of saccades (c), duration of saccades (e), and saccade speed (f).
See this image and copyright information in PMC

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