The limits of fixation—Keeping the ametropic eye on target

Wahl, Siegfried; Dragneva, Denitsa; Rifai, Katharina

doi:10.1167/19.13.8

Cited by 5 publications

(8 citation statements)

References 30 publications

(39 reference statements)

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“…On the two sides of each graph, the red numbers around the center of each location were the gaze positions extracted during the test. The amblyopic participant showed poor accuracy and precision in static and post-saccadic fixation, while the participant with recovered amblyopia showed similar results with the control properties [14,21]. During sustained fixation, amplitude and rate of microsaccades increased with increasing refractive errors [21].…”

Section: Discussionmentioning

confidence: 66%

“…In amblyopic children, fixation deviations were found similar between myopes and hyperopes, and were independent of refractive errors as well. A possible reason was that in this study, the experiment was performed under corrected vision to avoid the influence of measurement errors under naked-eye viewing on the fixation accuracy [21]. However, it might obscure the effect of refractive errors at the same time, since a study found an increase in the amplitude of microsaccades under viewing with uncorrected refraction compared to corrected refraction [14].…”

Section: Discussionmentioning

confidence: 99%

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Quantitative assessment of eye movements using a binocular paradigm: comparison among amblyopic, recovered amblyopic and normal children

Zhou

Bian

et al. 2022

BMC Ophthalmol

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Background To investigate the eye movement functions in children with amblyopia and recovered amblyopia by a binocular eye-tracking paradigm. Methods Eye movements of 135 pediatric subjects (age range: 4–14 years), including 45 amblyopic children, 45 recovered amblyopic children and 45 age-similar normal controls, were recorded under binocular viewing with corrected refractive errors (if any). The deviation of gaze positions relative to the target location was recorded as the mean from both eyes. Main outcome measures included fixation deviations (degree) along horizontal and vertical axes in the sustained fixation test (Fix-X, Fix-Y) and visually guided saccade test (Sac-X, Sac-Y), which were compared across the three groups and between each two groups. Results All the four deviations were significantly larger in the amblyopia group compared to the other two groups, indicating increased inaccuracy of sustained and post-saccadic fixations in amblyopia. However, there was no significant difference in deviations between recovered amblyopic children and normal controls. Repeated measures showed similar results overall and within each group. Mild to moderate amblyopes and severe amblyopes did not differ in the four deviations. No significant interaction was found between subject groups and clinical characteristics (age, refractive status, and anisometropia). Conclusion Amblyopic children have poor eye movement functions with increased inaccuracy of sustained and post-saccadic fixations, which appear to be restored in children with recovered amblyopia. Binocular assessment of eye movements provides valuable indicators of functional recovery in amblyopia.

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Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Quantitative assessment of eye movements using a binocular paradigm: comparison among amblyopic, recovered amblyopic and normal children

Zhou

Bian

et al. 2022

BMC Ophthalmol

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“…The BCEA can be calculated using the following equation (Eq. 1) ( Timberlake et al, 2005 ; Pirdankar and Das, 2016 ; Wahl et al, 2019 ).…”

Section: Methodsmentioning

confidence: 99%

“…Various studies on fixation stability related to binocular functions using an eye tracker or a perimeter have been reported. These include the quantitative analysis of eye movements in the cover test, methods quantifying eye stability using the bivariate contour ellipse area (BCEA; Castet and Crossland, 2012 ), binocular coordination of each of the types of fixation eye movements ( Otero-Millan et al, 2014 ), the relationship between visual acuity and fixation stability ( Chung et al, 2015 ), and the impact of refractive error on eye fixation ( Wahl et al, 2019 ). Variations in the fixation of abnormal binocular functions have mostly been reported in strabismus.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Evaluation of the Association Between Fixation Stability and Phoria During Short-Term Binocular Viewing

et al. 2022

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PurposeFixation stability for binocular anomalies with a phoria cannot be detected by direct observations. This study aimed to quantitatively evaluate fixation stability using an eye tracker rather than direct directions in binocular vision with abnormal and normal phorias.MethodsThirty-five and 25 participants with abnormal and normal phoria, respectively, were included in the study. The horizontal and vertical gaze points and convergence were recorded for 10 s using a remote eye tracker while binocularly viewing a target on a display screen 550 mm away. Fixation stability was quantified using bivariate contour ellipse areas (BCEA).ResultsThe fixation stability for all participants-based evaluations as a single cluster in the abnormal phoria group was lower than that in the normal phoria group (p = 0.005). There was no difference between the two groups in the evaluation based on the BCEA for each participant-based evaluation (p = 0.66). Fixation stability was also more related to convergence for the abnormal phoria group than for the normal phoria group (r = 0.769, p < 0.001; r = 0.417, p = 0.038, respectively).ConclusionAs the first study to evaluate fixation stability using an eye-tracker to differentiate between abnormal and normal phoria for non-strabismus, these findings may provide evidence for improving the evaluation of binocular vision not detected with clinical diagnostic tests.

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“… Baskaran et al (2019) reported less torsional vergence amplitude in myopes than in emmetropes. Moreover, in several previous studies, the uncorrected refractive error resulted in unstable fixation ( Ko, Snodderly & Poletti, 2016 ; Yu et al, 2017 ; Wahl, Dragneva & Rifai, 2019 ); when the stimulus of fixation was weak, the amount of ocular torsion increase ( Choi et al, 2006 ). These previous studies indicate that uncorrected ametropia may affect ocular torsion.…”

Section: Introductionmentioning

confidence: 97%

The effect of uncorrected ametropia on ocular torsion induced by changes in fixation

Oh¹,

Moon²,

Cho³

et al. 2021

PeerJ

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Background and Objective Ocular torsion, the eye movements to rotating around the line of sight, has not been well investigated regarding the influence of refractive errors. The purpose of this study was to investigate the effect of uncorrected ametropia on ocular torsion induced by fixation distances. Methods Seventy-two subjects were classified according to the type of their refractive error, and ocular torsion of the uncorrected eye was compared based on changes induced by different fixation distances. Ocular torsion was measured using a slit-lamp biomicroscope equipped with an ophthalmic camera and a half-silvered mirror. Results In all groups, excyclotorsion values increased as the fixation distance decreased, but the myopia and astigmatism groups had larger amounts of ocular torsion than the emmetropia group. In addition, as the amount of uncorrected myopia and astigmatism increased, the amount of ocular torsion increased. Conclusion Since the amount of ocular torsion caused by a change to a shorter fixation distance was larger when the refractive error was uncorrected, we suggest that ametropia should be fully corrected in patients frequently exposed to ocular torsion due to changes in fixation distance.

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The limits of fixation—Keeping the ametropic eye on target

Cited by 5 publications

References 30 publications

Quantitative assessment of eye movements using a binocular paradigm: comparison among amblyopic, recovered amblyopic and normal children

Quantitative assessment of eye movements using a binocular paradigm: comparison among amblyopic, recovered amblyopic and normal children

Quantitative Evaluation of the Association Between Fixation Stability and Phoria During Short-Term Binocular Viewing

The effect of uncorrected ametropia on ocular torsion induced by changes in fixation

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