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Updated: Jul 23, 2025
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Assessing Binocular Central Visual Field and Binocular Eye Movements in a Dichoptic Viewing Condition
Published on: July 21, 2020
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Using a video-based eye tracker to analyse the binocular near-reflex dynamics response.
Julián Espinosa1,2, Kauzar Archid1, Jorge Pérez1,2
1Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, Alicante, Spain.
Summary
A new video-based eye-tracking system measures binocular near-reflex dynamics, including convergence, divergence, and pupil size. This cost-effective tool aids in understanding visual responses during accommodation and disaccommodation.
Area of Science:
- Ophthalmology
- Neuroscience
- Biomedical Engineering
Background:
- The binocular near-reflex response is crucial for clear vision at varying distances.
- Understanding its dynamics aids in diagnosing visual disorders and assessing effects of near work.
- Previous methods lacked simultaneous measurement of all three components.
Purpose of the Study:
- To introduce a novel video-based eye-tracking system for analyzing near-reflex dynamics.
- To enable simultaneous measurement of convergence, divergence, and pupillary size.
- To provide a comprehensive understanding of the three-component near-reflex.
Main Methods:
- Utilized a high-speed (90 Hz) video-based eye tracker with 15 participants.
- Captured eye gaze and pupil radius changes during accommodation and disaccommodation.
- Applied offline analysis with hyperbolic tangent function fitting to characterize response dynamics.
Main Results:
- Observed significant temporal differences in pupil radius dynamics (miosis faster than mydriasis).
- Found longer convergence times compared to vertical saccades.
- Steady-state values for gaze and pupil size aligned with theoretical expectations.
Conclusions:
- The system offers a non-invasive, portable, and cost-effective method for evaluating near-reflex dynamics.
- High sampling rate ensures accurate assessment of vergence and pupillary dynamics.
- Simultaneous measurement provides a comprehensive view, valuable for clinical diagnosis and research.
