Colour contrast thresholds are normal in functional amblyopia

Mangelschots, E; Beerlandt, Nancy; Janssens, Hilde; Spileers, Werner

doi:10.1038/eye.1996.106

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…Reduction in sensitivity for red/green chromatic stimuli has been described in amblyopic eyes, 16,17 though interestingly there is much less effect for blue/yellow stimuli. 16,18 The present findings using a red/green isoluminant stimulus are in general accord with these previous studies.…”

Section: Discussionsupporting

confidence: 82%

Differential Changes of Magnocellular and Parvocellular Visual Function in Early- and Late-Onset Strabismic Amblyopia

Davis

Sloper

Neveu

et al. 2006

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.Studies in nonhuman primates show that monocular visual deprivation starting at different ages has different effects on cells in the parvocellular and magnocellular laminae of the lateral geniculate nucleus. The present study used color and luminance contrast sensitivity (CS) measurements to look for differences in parvocellular-and magnocellular-related visual function in human subjects with strabismic amblyopia. METHODS. Fifteen subjects with early-and 14 with late-onset strabismic amblyopia and similar ranges of visual acuity were studied, together with 15 subjects with normal vision. Contrast sensitivities were measured to an equiluminant (L-M conemodulated) grating with slow onset and an achromatic (LϩM cone-modulated) 0.8-cpd grating with rapid onset using an adaptive method. RESULTS. Luminance and color CS were lower in the amblyopic eyes than in the fellow eyes of all amblyopes. For luminance CS, this was due both to an increase in sensitivity of the fellow eye and to a reduction in sensitivity in the amblyopic eye. Color CS was greatly reduced in the amblyopic and fellow eyes of subjects with strabismic amblyopia of early-and late onset compared with subjects with normal vision. The reduction in color CS compared with luminance CS was significantly greater in eyes with late-rather than early-onset amblyopia. CONCLUSIONS. Parvocellular and magnocellular function are differentially affected in the amblyopic and fellow eyes of subjects with strabismic amblyopia. The difference is more marked in late-onset amblyopia than in early-onset amblyopia. (Invest Ophthalmol Vis Sci. 2006;47:4836 -4841)

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Section: Discussionsupporting

confidence: 82%

Differential Changes of Magnocellular and Parvocellular Visual Function in Early- and Late-Onset Strabismic Amblyopia

Davis

Sloper

Neveu

et al. 2006

Invest. Ophthalmol. Vis. Sci.

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“…There is evidence that patches are specialized for the processing of color information (Livingstone and Hubel, 1984; Lu and Roe, 2008). Relative sparing of patches could explain why color perception seems to be impaired less severely than spatial resolution in patients with amblyopia (Mangelschots et al, 1996; Almog and Nemet, 2010). However, there is some doubt that color and form are handled by largely segregated cell populations in V1, implying that color processing may not be limited to patches (Gegenfurtner and Kiper, 2003; Shapley and Hawken, 2011).…”

Section: Discussionmentioning

confidence: 99%

Neuronal Projections from V1 to V2 in Amblyopia

Sincich

Jocson²,

Horton³

2012

J. Neurosci.

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The mechanism of amblyopia in children with congenital cataract is not understood fully, but studies in macaques have shown that geniculate synapses are lost in striate cortex (V1). To search for other projection abnormalities in amblyopia, the pathway from V1 to V2 was examined using a triple-label technique in 3 animals raised with monocular suture. [3H]proline was injected into one eye to label the ocular dominance columns. Cholera toxin B-gold (CTB-Au) was injected in V2 to label V1 projection neurons. Alternate sections were processed for cytochrome oxidase (CO) and CTB-Au, or dipped for autoradiography. Eight fields of CTB-Au-labeled cells in V1 opposite injection sites were plotted in layers 2/3 or 4B. After thin stripe injection, labeled cells were concentrated in CO patches. Despite column shrinkage, cells in deprived and normal columns were equal in size and density, in both layer 2/3 and 4B. After pale or thick stripe injection, labeled cells were concentrated in interpatches. Only 23% of projection neurons originated from deprived columns. This reduction exceeded the degree of column shrinkage, a result explained by the fact that column shrinkage causes disproportionate loss of interpatch territory. These data indicate that early monocular form deprivation does not alter the segregation of patch and interpatch pathways to V2 stripes, or cause selective loss or atrophy of V1 projection neurons. The effect of shrinkage of geniculocortical afferents in layer 4C following visual deprivation is not amplified further by attenuation of the amblyopic eye’s projections from V1 to V2.

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“…A visão de cores é muito pouco estudada na ambliopia, e os poucos trabalhos pioneiros não encontraram alteração ou acharam dados inconsistentes nos pacientes amblíopes (Ball 1972, Bradley et al 1986, Mangelschots et al 1996.…”

Section: Visão De Coresunclassified

“…A diferença de AV entre os olhos não dominantes de amblíopes e controles também foi mantida após análise dos subtipos, na qual todos os grupos de ambliopia são piores que os controles, porém, o grupo de ambliopia mista teve pior desempenho comparado a outros grupos. Este resultado reforça os achados prévios na literatura indicando que a ambliopia mista, muito provavelmente, por ser causada pela combinação de dois fatores ambliopiogênicos (estrabismo + anisometropia) tem como consequência o acometimento mais importante da acuidade visual em relação aos subtipos isolados (Wong 2012, Harrad 1996, Hess and Baker Jr 1984, Barrett et al 2004 (Costa et al 2006), nossos dados concordam com estudos anteriores que não encontraram alterações na discriminação de cores na ambliopia (Ball 1972, Mangelschots et al 1996. Pode-se inferir que este resultado sugere que o processamento de cor dominado por processamentos funcionais em níveis iniciais (retina) está poupado na ambliopia de todos os tipos etiológicos estudados.…”

Section: Materials E Métodos Daunclassified

Impacto da ambliopia estrabísmica e anisometrópica na visão de cores e de contraste espacial com diferentes níveis de complexidade

Zagui¹

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Colour contrast thresholds are normal in functional amblyopia

Cited by 5 publications

References 11 publications

Differential Changes of Magnocellular and Parvocellular Visual Function in Early- and Late-Onset Strabismic Amblyopia

Differential Changes of Magnocellular and Parvocellular Visual Function in Early- and Late-Onset Strabismic Amblyopia

Neuronal Projections from V1 to V2 in Amblyopia

Impacto da ambliopia estrabísmica e anisometrópica na visão de cores e de contraste espacial com diferentes níveis de complexidade

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