Suppression Rather Than Visual Acuity Loss Limits Stereoacuity in Amblyopia

Webber, Ann; Schmid, Katrina L.; Baldwin, Alex S.; Hess, Robert F.

doi:10.1167/iovs.61.6.50

Cited by 28 publications

(24 citation statements)

References 46 publications

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“…This suppression along with impaired correspondence matching due to interocular differences in image quality, 40 may explain the stereoacuity losses demonstrated previously in keratoconus. 41 Stereoacuities measured in this study using the clinical Randot test do not provide enough resolution to compare against the psychophysical measures of suppression recorded here. The exact relation between suppression depth and stereoacuity thus remains unknown in keratoconus and needs further investigation.…”

Section: Discussionmentioning

confidence: 63%

Contrast Rivalry Paradigm Reveals Suppression of Monocular Input in Keratoconus

Marella

Conway

Suttle

2021

Invest. Ophthalmol. Vis. Sci.

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Purpose Keratoconus results in image quality loss in one or both eyes due to increased corneal distortion. This study quantified the depth of monocular suppression in keratoconus due to this image quality loss using a binocular contrast rivalry paradigm. Methods Contrast rivalry was induced in 50 keratoconic cases (11–31 years) and 12 age-matched controls by dichoptically viewing orthogonal Gabor patches of 5 cycles per degree (cpd) and 1.5 cpd spatial frequency for 120 seconds with their best-corrected spectacles and rigid gas permeable (RGP) contact lenses. The dwell time on each eye's percept was determined at baseline (100% contrast bilaterally) and at varying contrast levels (80–2.5%) in the stronger eye of keratoconus or dominant eye of controls. The contrast reduction needed in the stronger eye to balance dwell times on both eyes was considered a measure of suppression depth. Results At baseline with 5 cpd stimuli and spectacle correction, the rivalry switches were less frequent and biased toward the stronger eye of cases, all relative to controls ( P < 0.001). The contrast balance point of cases (20.51% [10.7–61%]) was lower than the controls (99.80% [98.6–100%]; P < 0.001) and strongly associated with the overall and interocular difference in disease severity ( r = 0.83, P < 0.001). The suppression depth reduced for 1.5 cpd (70.8% [21.7–94%]), relative to 5 cpd stimulus ( P < 0.001) and with contact lenses (80.1% [49.5–91.7%]), relative to spectacles ( P < 0.001). Conclusions The eye with lesser disease severity dominates binocular viewing in keratoconus. The suppression depth of the poorer eye depends on the extent of bilateral disease severity, optical correction modality, and the target spatial frequency.

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Section: Discussionmentioning

confidence: 63%

Contrast Rivalry Paradigm Reveals Suppression of Monocular Input in Keratoconus

Marella

Conway

Suttle

2021

Invest. Ophthalmol. Vis. Sci.

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“…There are also studies suggest that binocular imbalance (the interocular contrast ratio at where the two eyes are balanced in binocular combination/rivalry) is correlated with that of stereopsis in amblyopes ( Han et al., 2018 ; He et al., 2018 ; Li et al., 2011 ). In addition, several anti-suppression training studies show that amblyopes' stereopsis improves as a result of reducing suppression ( Vedamurthy et al., 2015 ; Hess et al., 2010a ; Webber et al., 2020 ). We thus choose the binocular orientation combination task to quantify the binocular performance of treated amblyopes in our study.…”

Section: Discussionmentioning

confidence: 99%

Binocular visual deficits at mid to high spatial frequency in treated amblyopes

et al. 2021

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“…Visually normal adults and amblyopes differ in terms of their performance-limiting mechanisms. In amblyopes, suppression is assumed to be the primary factor that limits stereopsis, 51 resulting in disrupted binocular combination under ordinary viewing conditions. 52 , 53 Therefore, reducing suppression and promoting binocular combination may provide meaningful gains in (likely coarse) stereoscopic function.…”

Section: Discussionmentioning

confidence: 99%

Dichoptic Perceptual Training and Sensory Eye Dominance Plasticity in Normal Vision

Kam

Chang

2021

Invest. Ophthalmol. Vis. Sci.

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Purpose We introduce a set of dichoptic training tasks that differ in terms of (1) the presence of external noise and (2) the visual feature implicated (motion, orientation), examining the generality of training effects between the different training and test cues and their capacity for driving changes in sensory eye dominance and stereoscopic depth perception. Methods We randomly assigned 116 normal-sighted observers to five groups (four training groups and one no training group). All groups completed both pre- and posttests, during which they were tested on dichoptic motion and orientation tasks under noisy and noise-free conditions, as well as a binocular phase combination task and two depth tasks to index sensory eye dominance and binocular function. Training groups received visual training on one of the four dichoptic tasks over 3 consecutive days. Results Training under noise-free conditions supported generalization of learning to noise-free tasks involving an untrained feature. By contrast, there was a symmetric learning transfer between the signal-noise and no-noise tasks within the same visual feature. Further, training on all tasks reduced sensory eye dominance but did not improve depth perception. Conclusions Training-driven changes in sensory eye balance do not depend on the stimulus feature or whether the training entails the presence of external noise. We conjecture that dichoptic visual training acts to balance interocular suppression before or at the site of binocular combination.

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Suppression Rather Than Visual Acuity Loss Limits Stereoacuity in Amblyopia

Cited by 28 publications

References 46 publications

Contrast Rivalry Paradigm Reveals Suppression of Monocular Input in Keratoconus

Contrast Rivalry Paradigm Reveals Suppression of Monocular Input in Keratoconus

Binocular visual deficits at mid to high spatial frequency in treated amblyopes

Dichoptic Perceptual Training and Sensory Eye Dominance Plasticity in Normal Vision

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