A dichoptic feedback-based oculomotor training method to manipulate interocular alignment

Invest. Ophthalmol. Vis. Sci.

Kwon

2023

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Purpose To examine how binocularly asymmetric glaucomatous visual field damage affects binocular disparity processing across the visual field. Methods We recruited 18 patients with primary open-angle glaucoma, 16 age-matched controls, and 13 young controls. Participants underwent standard clinical assessments of binocular visual acuity, binocular contrast sensitivity, stereoacuity, and perimetry. We employed a previously validated psychophysical procedure to measure how sensitivity to binocular disparity varied across spatial frequencies and visual field sectors (i.e., with full-field stimuli spanning the central 21° of the visual field and with stimuli restricted to annular regions spanning 0°–3°, 3°–9°, or 9°–21°). We employed measurements with annular stimuli to model different possible scenarios regarding how disparity information is combined across visual field sectors. We adjudicated between potential mechanisms by comparing model predictions to the patterns observed with full-field stimuli. Results Perimetry confirmed that patients with glaucoma exhibited binocularly asymmetric visual field damage ( P < 0.001). Across participant groups, foveal regions preferentially processed disparities at finer spatial scales, whereas periphery regions were tuned for coarser scales ( P < 0.001). Disparity sensitivity also decreased from fovea to periphery ( P < 0.001) and across participant groups ( P s < 0.01). Finally, similar to controls, patients with glaucoma exhibited near-optimal disparity integration, specifically at low spatial frequencies ( P < 0.001). Conclusions Contrary to the conventional view that glaucoma spares central vision, we find that glaucomatous damage causes a widespread loss of disparity sensitivity across both foveal and peripheral regions. Despite these losses, cortical integration mechanisms appear to be well preserved, suggesting that patients with glaucoma make the best possible use of their remaining binocular function.

Section: Discussionmentioning

confidence: 94%

Despite Impaired Binocular Function, Binocular Disparity Integration Across the Visual Field Is Spared in Normal Aging and Glaucoma

Invest. Ophthalmol. Vis. Sci.

Kwon

2023

Self Cite

Section: Discussionmentioning

confidence: 95%

“…While such findings hint at potential treatment opportunities for preserving or restoring binocular function 32,[66][67][68][69][70] in early or moderate glaucoma, we acknowledge that whether this would occur also in more advanced disease stages needs to be addressed in future studies. In addition, more quantitative assessments 25,36,71,72 of the relationship between the pattern of glaucomatous visual field defects and the pattern of impairment in disparity processing would help us further characterize binocular disparity processing throughout the visual field.…”

Section: Discussionmentioning

confidence: 95%

Despite impaired binocular function, binocular disparity integration across the visual field is spared in normal aging and glaucoma

Kwon

2022

Preprint

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Objective: To examine how binocularly asymmetric glaucomatous visual field damage affects processing of binocular disparity across the visual field. Design: Case-control study. Participants and Controls: A sample of 18 patients with primary open-angle glaucoma, 16 age-matched controls, and 13 young controls. Methods: Participants underwent standard clinical assessments of binocular visual acuity, binocular contrast sensitivity, stereoacuity, and perimetry. We employed a previously validated psychophysical procedure to measure how sensitivity to binocular disparity varied across spatial frequencies and visual field sectors, i.e. with full-field stimuli spanning the central 21° of the visual field, and with stimuli restricted to annular regions spanning 0°-3°, 3°-9° or 9°-21°. Main Outcome Measures: We verified the presence of binocularly asymmetric glaucomatous visual field damage by comparing—between the two eyes—the mean deviation values obtained from the Humphrey Field Analyzer (HFA) 24-2 test. To assess the spatial-frequency tuning of disparity sensitivity across the visual field of patients and controls, we fit disparity sensitivity data to log-parabola models and compared fitted model parameters. Lastly, we employed disparity sensitivity measurements from restricted visual field conditions to model different possible scenarios regarding how disparity information is combined across visual field sectors. We adjudicated between the potential mechanisms by comparing model predictions to the observed patterns of disparity sensitivity with full-field stimuli. Results: The interocular difference in HFA 24-2 mean deviation was greater in glaucoma patients compared to both young and age-matched controls (ps=.01). Across participant groups foveal regions preferentially processed disparities at finer spatial scales, whereas periphery regions were tuned for coarser scales (p<.001). Disparity sensitivity also decreased from the fovea to the periphery (p<.001) and across participant groups (ps<.01). Finally, similar to controls, glaucoma patients exhibited near-optimal disparity integration, specifically at low spatial frequencies (p<.001). Conclusions: Contrary to the conventional view that glaucoma spares central vision, we find that glaucomatous damage causes a widespread loss of disparity sensitivity across both foveal and peripheral regions. Despite these losses, cortical integration mechanisms appear to be well preserved, suggesting that glaucoma patients make the best possible use of their remaining binocular function.

“…In future research, we plan to deploy this method to investigate and model visually guided grasping behavior in humans 16 . We further plan to integrate these tools with eye tracking 47,[51][52][53] and virtual/augmented reality systems [54][55][56] to investigate visually guided hand and eye movement motor control in real and virtual naturalistic environments 18,47,57,58 . For these reasons, the proposed method could be of interest to researchers studying haptic perception 59 , motor control, and human-computer interaction in virtual and augmented reality.…”

Section: Limitations and Future Directionsmentioning

confidence: 99%

A method to estimate contact regions between hands and objects during human multi-digit grasping

Hartmann

Rothkopf

et al. 2022

Preprint

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In order to grasp an object successfully, we must select appropriate contact regions for our hands on the surface of the object. However, identifying such regions is challenging. Here, we describe a workflow to estimate contact regions from marker-based tracking data. Participants grasp real objects, while we track the 3D position of both the objects and the hand including the fingers' joints. We first determine joint Euler angles from a selection of tracked markers positioned on the back of the hand. Then, we use state-of-the-art hand mesh reconstruction algorithms to generate a mesh model of the participant's hand in the current pose and 3D position. Using objects that were either 3D printed, or 3D scanned—and are thus available as both real objects and mesh data—allows us to co-register the hand and object meshes. In turn, this allows us to estimate approximate contact regions by calculating intersections between the hand mesh and the co-registered 3D object mesh. The method may be used to estimate where and how humans grasp objects under a variety of conditions. Therefore, the method could be of interest to researchers studying visual and haptic perception, motor control, human-computer interaction in virtual and augmented reality, and robotics.