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Quantitative analysis of ocular deviation under eye occlusion: a descriptive study using the ORTe EYENAC eye-tracking
Shunya Tatara1, Yuna Magara2,3, Touko Sasaki2,4
1Department of Orthoptics and Visual Sciences, Niigata University of Health and Welfare, Niigata, Japan. tatara@nuhw.ac.jp.
BMC Ophthalmology
|May 6, 2025
Summary
Video-oculography with the ORTe EYENAC system effectively visualizes ocular deviation during occlusion in individuals with exodeviation. Stabilization time for fusion-free eye position averaged 3.33 seconds, varying with deviation angle.
Area of Science:
- Ophthalmology
- Vision Science
- Biomedical Engineering
Background:
- Traditional cover tests for heterotropia and heterophoria are qualitative or time-consuming.
- Alternate prism cover test (APCT) quantifies ocular deviations but has interexaminer variability.
- Video-oculography offers a promising, objective method for quantifying ocular deviation under occlusion.
Purpose of the Study:
- To visualize ocular deviation during occlusion using the ORTe EYENAC eye-tracking system.
- To determine the stabilization time of ocular deviation in participants with exodeviation.
Main Methods:
- 15 university students (aged 20-22) with exodeviation participated.
- Eye position was measured using the ORTe EYENAC during monocular occlusion.
- Data were fitted to a logistic function to estimate deviation, speed, and stabilization time.
Main Results:
- Fusion-free eye position stabilized at 3.33 ± 2.39 seconds in participants with exophoria.
- Significant correlations were found between deviation angle and speed (rs = -0.582), and angle and stabilization time (rs = 0.663).
- Overshoot depth correlated significantly with deviation speed (rs = 0.775).
Conclusions:
- The ORTe EYENAC system effectively visualizes ocular deviation under occlusion in exodeviation.
- Stabilization time varied with the angle of ocular deviation.
- Occlusion duration should be individualized based on the specific angle of strabismus.
