Assessment of binocular fixational eye movements including cyclotorsion with split-field binocular scanning laser ophthalmoscopy

Hofmann, Julia; Domdei, Lennart; Jainta, Stephanie; Harmening, Wolf M.

doi:10.1167/jov.22.10.5

Cited by 6 publications

(3 citation statements)

References 56 publications

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“…The frame-wise (30 Hz) stimulus position was encoded as a white cross marker in each video. As single strip alignments can have small errors due to noise in the strip or retinal torsion (particularly affecting the horizontal motion estimate) 75 , we compute the average offsets from the cross-containing strip and 2 previous/subsequent strips. These steps yielded more accurate trajectories in retinal coordinates for every trial.…”

Section: Methodsmentioning

confidence: 99%

Sub-cone visual resolution by active, adaptive sampling in the human foveola

Witten,

Lukyanova,

Harmening

2024

Preprint

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The foveated architecture of the human retina and the eye's mobility enable prime spatial vision, yet the interplay between photoreceptor cell topography and the constant motion of the eye during fixation remains unexplored. Within vivofoveal cone-resolved imaging and simultaneous microscopic photo stimulation, we examined visual acuity in both eyes of 16 participants while precisely recording the stimulus path on the retina. We find that resolution thresholds were correlated with the individual retina's sampling capacity, and exceeded what static sampling limits would predict by 18 %, on average. The amplitude and direction of fixational drift motion, previously thought to be primarily random, played a key role in achieving this sub-cone diameter resolution. The oculomotor system finely adjusts drift behavior towards retinal areas with higher cone densities within only a few hundred milliseconds to enhance retinal sampling.

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Section: Methodsmentioning

confidence: 99%

Sub-cone visual resolution by active, adaptive sampling in the human foveola

Witten,

Lukyanova,

Harmening

2024

Preprint

Self Cite

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show abstract

“…The superior and inferior oblique muscles assist in the torsional movement of the eyeball. Torsional eye movements, characterized by minimal overall variability (approximately 0.10 • ), are an unconscious reflex and strictly physiologically controlled [21]. The superior and inferior rectus muscles rotate the eyeball around the horizontal axis, and the lateral and medial rectus muscles allow the eyeball to rotate around the vertical axis.…”

Section: Gaze Mechanisms Of Human Eyesmentioning

confidence: 99%

“…Fan et al [20] designed a bionic eye that could tilt, pan, and roll with six servo motors. However, a rolling motion is generally not required for a device that imitates the gaze function [21]. Some studies have focused on the design of devices that can tilt and pan with four servo motors [22,23].…”

Section: Introductionmentioning

confidence: 99%

The Design and Control of a Biomimetic Binocular Cooperative Perception System Inspired by the Eye Gaze Mechanism

Qin,

Xia,

et al. 2024

Biomimetics

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Research on systems that imitate the gaze function of human eyes is valuable for the development of humanoid eye intelligent perception. However, the existing systems have some limitations, including the redundancy of servo motors, a lack of camera position adjustment components, and the absence of interest-point-driven binocular cooperative motion-control strategies. In response to these challenges, a novel biomimetic binocular cooperative perception system (BBCPS) was designed and its control was realized. Inspired by the gaze mechanism of human eyes, we designed a simple and flexible biomimetic binocular cooperative perception device (BBCPD). Based on a dynamic analysis, the BBCPD was assembled according to the principle of symmetrical distribution around the center. This enhances braking performance and reduces operating energy consumption, as evidenced by the simulation results. Moreover, we crafted an initial position calibration technique that allows for the calibration and adjustment of the camera pose and servo motor zero-position, to ensure that the state of the BBCPD matches the subsequent control method. Following this, a control method for the BBCPS was developed, combining interest point detection with a motion-control strategy. Specifically, we propose a binocular interest-point extraction method based on frequency-tuned and template-matching algorithms for perceiving interest points. To move an interest point to a principal point, we present a binocular cooperative motion-control strategy. The rotation angles of servo motors were calculated based on the pixel difference between the principal point and the interest point, and PID-controlled servo motors were driven in parallel. Finally, real experiments validated the control performance of the BBCPS, demonstrating that the gaze error was less than three pixels.

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The preferred retinal loci when the eyes converge

Bowers,

Gautier,

Chung

et al. 2024

Journal of Vision

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The preferred retinal locus (PRL) is the position on the retina to which humans direct stimuli during fixation. In healthy normal eyes, it has been shown to be very stable across time and between different tasks. Previous measurements of the PRL have been made under monocular viewing conditions. The current study examines where the PRLs in the two eyes’ retinas are when subjects fixate binocularly and whether they shift when the demand for the eyes to converge is changed. Our apparatus allows us to see exactly where binocular stimuli fell on the two retinas during binocular fixation. Thus, our technique bypasses some of the issues involved in measuring binocular alignment with subjective techniques and previous objective techniques that use conventional eye trackers. These results show that PRLs shift slightly but systematically as the demand for convergence increases. The shifts cause under-convergence (also called exo fixation disparity) for near targets. They are not large enough to cause a break in binocular fusion. The fixation disparity we observed with increasing vergence demand is similar to fixation disparity observed in previous reports.

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Assessment of binocular fixational eye movements including cyclotorsion with split-field binocular scanning laser ophthalmoscopy

Cited by 6 publications

References 56 publications

Sub-cone visual resolution by active, adaptive sampling in the human foveola

Sub-cone visual resolution by active, adaptive sampling in the human foveola

The Design and Control of a Biomimetic Binocular Cooperative Perception System Inspired by the Eye Gaze Mechanism

The preferred retinal loci when the eyes converge

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