Orientation Discrimination with Macular Changes Associated with Early AMD

Bedell, Harold E.; Tong, Jianliang; Woo, Stanley; House, James R.; Nguyen, Tammy

doi:10.1097/opx.0b013e31819fa6e2

Cited by 13 publications

(21 citation statements)

References 29 publications

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“…This extrafoveal vision has lower spatial resolution compared to foveal vision. Many studies on low-level visual processing have illustrated the immediate consequences of the loss of foveal vision, e.g., reduced visual acuity and contrast sensitivity (Qiu and Leat, 2009) and deficits in orientation discrimination (Bedell et al, 2009) and shape discrimination (Wang et al, 2002). For a review on psychophysical function in AMD, see Neelam et al (2009).…”

Section: Introductionmentioning

confidence: 99%

Simulated loss of foveal vision eliminates visual search advantage in repeated displays

Geringswald¹,

Baumgartner²,

Pollmann³

2012

Front. Hum. Neurosci.

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In the contextual cueing paradigm, incidental visual learning of repeated distractor configurations leads to faster search times in repeated compared to new displays. This contextual cueing is closely linked to the visual exploration of the search arrays as indicated by fewer fixations and more efficient scan paths in repeated search arrays. Here, we examined contextual cueing under impaired visual exploration induced by a simulated central scotoma that causes the participant to rely on extrafoveal vision. We let normal-sighted participants search for the target either under unimpaired viewing conditions or with a gaze-contingent central scotoma masking the currently fixated area. Under unimpaired viewing conditions, participants revealed shorter search times and more efficient exploration of the display for repeated compared to novel search arrays and thus exhibited contextual cueing. When visual search was impaired by the central scotoma, search facilitation for repeated displays was eliminated. These results indicate that a loss of foveal sight, as it is commonly observed in maculopathies, e.g., may lead to deficits in high-level visual functions well beyond the immediate consequences of a scotoma.

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Section: Introductionmentioning

confidence: 99%

Simulated loss of foveal vision eliminates visual search advantage in repeated displays

Geringswald¹,

Baumgartner²,

Pollmann³

2012

Front. Hum. Neurosci.

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“…Other methods may achieve the same effect. In a recent paper, Bedell et al found that early AMD patients with normal visual acuity had more difficulty in judging the orientation uniformity of a patch of line segments than normal subjects 58. The key feature of this sensitive test was the selection of length of the line segments.…”

Section: Discussionmentioning

confidence: 99%

Early Age-Related Macular Degeneration Impairs Tolerance to Stimulus Degradation

Liu

White²

2010

Optometry and Vision Science

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Purpose Pathologic changes of retinal photoreceptors associated with early age-related macular degeneration (AMD) have been well established, but the disease is usually asymptomatic at the early stage and traditional suprathreshold clinical tests often fail to reveal functional deficiencies. The aim of this study is to demonstrate subtle changes of one suprathreshold visual function in early AMD eyes. Methods The quality of pre-attentively discriminable texture stimuli was systematically degraded through random deletion of texture checks. The subjects’ task was to make a forced-choice decision on whether two equally degraded patches contained samples of the same or different types of textures. Tolerance to texture stimulus degradation was measured in young and elderly normal controls and in patients with early AMD. Results Subjects were trained to perform the texture discrimination task until they made few errors in discriminating intact textures. Texture discrimination deteriorated with increasing stimulus degradation in all subjects. There was no significant difference between performance of young and elderly normal controls. Early AMD eyes showed significantly less tolerance to stimulus degradation than age-similar normal controls at a range of degradation levels. After controlling for visual acuity, normal subjects still performed significantly better than early AMD eyes around 22% check deletion. There was no significant difference between better eyes of early AMD patients and fellow eyes of late AMD eyes. Performance on the degraded texture task was not correlated with visual acuity. A mild blur of the stimulus had little effect on discrimination of degraded textures. Conclusions Early AMD may not directly affect suprathreshold visual functions when the stimuli are intact and contain redundant information, but may manifest itself as a reduction of tolerance to stimulus degradation in the form of localized information loss. The performance of patients with early AMD may be compromised when the visual stimulus contains less redundant information.

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“…However, none of those methods are firmly established or clinically routine. Recently, Bedell et al developed a functional test based on the orientation discrimination threshold (ODT) that proved effective in identifying patients in the early stage of AMD [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Relationships of orientation discrimination threshold and visual acuity with macular lesions in age-related macular degeneration

Zhang

Tong

et al. 2017

PLoS ONE

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PurposeTo measure visual acuity and metamorphopsia in patients with age-related macular degeneration (AMD) and to explore their relationship with macular lesions.MethodsIn this cross-sectional study, a total of 32 normal subjects (32 eyes) and 35 AMD patients (35 eyes) were recruited. They were categorized into 4 groups: normal, dry AMD, non-active wet AMD, and active wet AMD. Best-corrected visual acuity (BCVA) was measured using the Early Treatment Diabetic Retinopathy Study protocol. Metamorphopsia was quantified with the orientation discrimination threshold (ODT). Macular lesions, including drusen, sub-retinal fluid (SRF), intra-retinal fluid (IRF), pigmented epithelium detachment (PED), and scarring, were identified with spectral-domain optical coherence tomography (SD-OCT). A linear regression model was established to identify the relationships between the functional and structural changes.ResultsBCVA progressively worsened across the normal, dry AMD, non-active wet AMD, and active wet AMD groups (P < 0.001), and ODT increased across the groups (P < 0.001). The correlation between BCVA and ODT varied among the groups. The partial correlation between BCVA and ODT was −0.61 (P < 0.001). Linear regression showed that ODT significantly depended on IRF (β = 0.61, P < 0.001), SRF (β = 0.34, P = 0.003), and scarring (β = 0.26, P = 0.050), while BCVA significantly depended only on scarring (β = −0.52, P < 0.001), and IRF (β = −0.36, P = 0.016).ConclusionsFrom dry AMD to active wet AMD, BCVA gradually worsened while ODT increased. The correlation between BCVA and ODT varied among these groups, indicating that AMD lesions affect them differently. ODT and BCVA should be used concurrently for better monitoring of the disease.

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Orientation Discrimination with Macular Changes Associated with Early AMD

Cited by 13 publications

References 29 publications

Simulated loss of foveal vision eliminates visual search advantage in repeated displays

Simulated loss of foveal vision eliminates visual search advantage in repeated displays

Early Age-Related Macular Degeneration Impairs Tolerance to Stimulus Degradation

Relationships of orientation discrimination threshold and visual acuity with macular lesions in age-related macular degeneration

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