A rapid quantification of binocular misalignment without recording eye movements: Vertical and torsional alignment nulling

Beaton, K.; Shelhamer, Mark; Roberts, Dale; Schubert, Michael C.

doi:10.1016/j.jneumeth.2017.03.009

Cited by 5 publications

(7 citation statements)

References 20 publications

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“…They concluded that VAN and TAN were valid measures of ocular misalignment in the context of the space environment. VAN and TAN have recently been validated against prism diopter and established as reliable over repeated measures [2]. …”

Section: Introductionmentioning

confidence: 99%

Prototype tests of vertical and torsional alignment nulling for screening vestibular function

Schubert

Stitz

Cohen

et al. 2017

VES

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Background We have developed a non-invasive, behavioral measure of ocular alignment using a computer tablet, colored lenses, and touch screen software. Objective The goal of this study was to determine if these tests differentiate healthy controls from patients with vestibular disorders. Methods In the vertical alignment nulling test (VAN), subjects were asked to adjust a horizontal line that was offset vertically from a fixed horizontal line. In the torsional alignment nulling test (TAN) subjects were asked to adjust a line that was rotationally offset (i.e. clockwise) from a fixed horizontal line. We measured VAN and TAN in 14 healthy controls and 8 patients with known vestibular disorders. Results Patients had significantly worse scores than controls on TAN, (mean 2.2 vs .75, p=0.01), and no differences for scores compared to controls on VAN, (mean .4 vs .8, p=0.07). Conclusions These results suggest that TAN, and possibly VAN, have potential for identifying misalignments in ocular position. After further technical development these tests might be useful in the future for screening patients in facilities that are not equipped to perform cervical and ocular vestibular evoked myogenic potentials.

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Section: Introductionmentioning

confidence: 99%

Prototype tests of vertical and torsional alignment nulling for screening vestibular function

Schubert

Stitz

Cohen

et al. 2017

VES

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“…Several attempts have been made to study ocular movements using images of different gaze positions [ 22 – 26 ]. Figueiredo et al [ 23 ] developed a web application using a CNN to classify eye versions into the nine gaze positions, but it was not clear how this could contribute to the actual examination of strabismus.…”

Section: Discussionmentioning

confidence: 99%

Automated Mathematical Algorithm for Quantitative Measurement of Strabismus Based on Photographs of Nine Cardinal Gaze Positions

Kang

Yang

Kim

et al. 2022

BioMed Research International

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This study presents an automated algorithm that measures ocular deviation quantitatively using photographs of the nine cardinal points of gaze by means of deep learning (DL) and image processing techniques. Photographs were collected from patients with strabismus. The images were used as inputs for the DL segmentation models that segmented the sclerae and limbi. Subsequently, the images were registered for the mathematical algorithm. Two-dimensional sclera and limbus were modeled, and the corneal light reflex points of the primary gaze images were determined. Limbus recognition was performed to measure the pixel-wise distance between the corneal reflex point and limbus center. The segmentation models exhibited high performance, with 96.88% dice similarity coefficient (DSC) for the sclera segmentation and 95.71% DSC for the limbus segmentation. The mathematical algorithm was tested on two cranial nerve palsy patients to evaluate its ability to measure and compare ocular deviation in different directions. These results were consistent with the symptoms of such disorders. This algorithm successfully measured the distance of ocular deviation in patients with strabismus. With complementation in the dimension calculations, we expect that this algorithm can be used further in clinical settings to diagnose and measure strabismus at a low cost.

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“…If a subject perfectly aligns the two lines during both VAN and TAN, then we infer that this individual has perfect vertical and torsional binocular alignment. For detail on the VAN and TAN method, please see Beaton et al 2017 [24].…”

Section: Methodsmentioning

confidence: 99%

“…The subject’s task is to adjust the moving line until it appears perfectly in-line with the stationary line, in other words to null any apparent vertical or rotational offset between the two lines. The test has been validated using prism diopters and video-oculography as well as during the altered gravitational environment of parabolic flight [23, 24]. The purpose of our study was to compare VAN and TAN between veterans and healthy controls in upright and supine test positions.…”

Section: Introductionmentioning

confidence: 99%

Veterans have greater variability in their perception of binocular alignment

Schubert

Gimmon²,

Millar

et al. 2018

PLoS ONE

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IntroductionA significant population of our wounded veterans suffer long-term functional consequences of visual deficit, disorientation, dizziness, and an impaired ability to read. These symptoms may be related to damage within the otolith pathways that contribute to ocular alignment. The purpose of this study was to compare perception of vertical and torsional ocular alignment between veterans and healthy controls in an upright and supine test position.Materials and methodsVeterans (n = 26) with reports of dizziness were recruited from the East Orange Veterans Administration Hospital. Healthy controls (n = 26) were recruited from both Johns Hopkins University and the East Orange VA. Each subject performed 20 trials each of a novel vertical and torsional binocular alignment perception test. Veterans underwent semicircular canal and otolith pathway function testing.Results88% of the Veterans had an absent otolith response. Only the veterans had an abnormally large variability in perception of both vertical and torsional ocular alignment, and in both upright and supine position. Neither post-traumatic stress disorder, nor depression contributed to the misperception in binocular alignment.ConclusionsOur novel method of measuring vertical and torsional misalignment distinguishes veterans with dizziness from healthy controls. The high prevalence of absent otolith function seems to explain this result. Further studies are needed to better understand the fundamental mechanism responsible for the increased variability of perception of binocular alignment.

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A rapid quantification of binocular misalignment without recording eye movements: Vertical and torsional alignment nulling

Abstract: VAN and TAN provide simple, sensitive, and quantitative measures of binocular positioning alignment that may be useful for detecting subtle abnormalities in ocular positioning.

Cited by 5 publications

References 20 publications

Prototype tests of vertical and torsional alignment nulling for screening vestibular function

Prototype tests of vertical and torsional alignment nulling for screening vestibular function

Automated Mathematical Algorithm for Quantitative Measurement of Strabismus Based on Photographs of Nine Cardinal Gaze Positions

Veterans have greater variability in their perception of binocular alignment

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