Gaze-dependent phoria and vergence adaptation

Dysli, Muriel; Abegg, Mathias

doi:10.1167/16.3.2

Cited by 9 publications

(3 citation statements)

References 38 publications

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“…secondary and tertiary eye positions were recorded at different angles of eccentricity in the Harms and Hess test. Since vergence demand and thus phoria changes with gaze position, 16 assessment of gaze-dependent measurement bias of screen tests would be particularly important in incomitant strabismus. As the Hess test is routinely carried out without refractive correction, we decided that all tests were performed without refractive correction for better comparability (except for two subjects).…”

Section: Discussionmentioning

confidence: 99%

Divergence bias in Hess compared to Harms screen strabismus testing

et al. 2021

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The Hess and the Harms screen test each have different testing distances. While the Harms screen test is usually performed at 2.5 m, the Hess screen test is performed at 0.5 m. The geometry of the closer testing distance of the Hess screen test requires an increase of the convergence angle by 6°. This study investigates the quantitative differences between the two frequently employed screen tests. Ocular deviation of 18 normal subjects and 36 patients with congenital or acquired paralytic or concomitant strabismus were assessed with a complete orthoptic examination including alternate prism cover testing at near (nPCT) and far (fPCT), as well as Hess and Harms screen testing. One-way ANOVA was used for statistical analysis. The Hess test recorded more overall exodeviation compared to the Harms test for patients (mean difference −3.50°, 95% limits of agreement (CI) = [−4.79, −2.21], p < .001), and controls (mean difference −1.78°, CI = [−2.99, −0.56], p = .004). For vertical deviations, there was no statistically significant difference between the two tests for patients (mean difference +0.75°, CI = [−0.41, +1.91], p = .251), and controls (mean difference −0.28°, CI = [−0.68, −0.11], p = 0.231). This study emphasizes the importance to consider the divergence bias when comparing the Hess to the Harms screen test, which is likely explained by the greater vergence demand dependent on the closer testing distance. The exodeviation shift tended to be more pronounced in patients than controls, which may imply that patients with strabismus have an impaired convergence drive.

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Section: Discussionmentioning

confidence: 99%

Divergence bias in Hess compared to Harms screen strabismus testing

et al. 2021

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“…How can human visual development inform machine learning and robotics (e.g., Vogelsang et al 2018, Zhu et al 2017? How do accommodation and vergence motor responses interact with other eye movements during development (e.g., Dysli & Abegg 2016, Oohira et al 1991? How does development of the first stages of visual processing impact higher-order extrastriate function, and what is the influence of topdown processes on basic sensory and motor visual development?…”

Section: What Comes Next?mentioning

confidence: 99%

The Importance of the Interaction Between Ocular Motor Function and Vision During Human Infancy

Candy

2019

Annu. Rev. Vis. Sci.

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Numerous studies have demonstrated the impact of imposed abnormal visual experience on the postnatal development of the visual system. These studies have provided fundamental insights into the mechanisms underlying neuroplasticity and its role in clinical care. However, the ocular motor responses of postnatal human infants largely define their visual experience in dynamic three-dimensional environments. Thus, the immature visual system needs to control its own visual experience. This review explores the interaction between the developing motor and sensory/perceptual visual systems, together with its importance in both typical development and the development of forms of strabismus and amblyopia.

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“…In contrast, vergence errors are frequent in pathological conditions such as strabismus. Strabismus can be manifest as in tropia where hetero‐tropia may take the different forms mentioned above such as eso‐, exo‐ and hyper‐ (Erkan Turan, Taylan Sekeroglu, Karahan, & Sanac, 2017), or latent as in phoria in which hetero‐phoria may vary the same way (Dysli & Abegg, 2016). In the latter (phoria), disparity is compensated by fusion, whereas it is no longer in the former (tropia; Cullen, 2015).…”

Section: Introductionmentioning

confidence: 99%

Measuring vergence and fixation disparity in 3D space

Duchesne

Coubard²

2020

Eur J of Neuroscience

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As the eyes continuously move in 3D space, they rarely converge at the exact depth of the plane even when fixating a 2D image or computer screen. Rather, the lines of gaze measured by eye movement recordings show some misalignment so‐called fixation disparity. Fixation disparity occurs in front of or behind the plane, and the eyes may also be lagged vertically. For those reasons, vision research requires mathematical tools to calculate where exactly the lines of gaze cross the stimulus plane. Seminal research on vergence eye movements targeting stimuli lying on isovergence curves has been content with simple computation of the difference between the two eye rotation angles. Recently, the need of new calculations has emerged with the increasing use of eye‐trackers providing the eye coordinates on a computer screen. Previous studies have made this attempt but with restrictions. We introduce here a complete calculation of fixation disparity in 3D space allowing vision researchers to study the precision of gaze regardless of the stimulus location in 3D space and of whether the eyes lag horizontally and/or vertically.

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Gaze-dependent phoria and vergence adaptation

Cited by 9 publications

References 38 publications

Divergence bias in Hess compared to Harms screen strabismus testing

Divergence bias in Hess compared to Harms screen strabismus testing

The Importance of the Interaction Between Ocular Motor Function and Vision During Human Infancy

Measuring vergence and fixation disparity in 3D space

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