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Contribution of chromatic mechanisms to the production of small-field optokinetic nystagmus (OKN) in normals and strabismics.

Authors :
Crognale MA
Schor CM
Source :
Vision research [Vision Res] 1996 Jun; Vol. 36 (11), pp. 1687-98.
Publication Year :
1996

Abstract

The contribution of chromatic mechanisms to motion processing is currently debated. Although OKN as a measure of motion processing has been employed for chromatic stimuli, the contribution of chromatic mechanisms to the production of OKN has not been assessed directly. We measured voluntary-pursuit and involuntary-stare OKN responses to drifting patterns defined by colors modulated in a cone based color space which isolates luminance and color mechanisms. Results show that OKN responses are reduced for isoluminant stimuli, particularly for the stare conditions. The greatest reduction in responses occur for isoluminance stimuli that isolate the S cones. These results suggest that the chromatic mechanisms may have reduced input to the neural substrate that produces involuntary-stare OKN or that stare OKN has different temporal characteristics when stimulated by chromatic and luminance mechanisms. We also measured OKN asymmetries in several convergent strabismics in response to isoluminant and luminance patterns and compared their response to previous reports of horizontal OKN asymmetries in normal neonate infants. The results question the validity of either the modeling of OKN asymmetries in strabismus as incomplete development or the comparison of adult eye movement records evaluated with criteria for OKN with psychophysical forced choice evaluation of ocular drift in infants.

Details

Language :
English
ISSN :
0042-6989
Volume :
36
Issue :
11
Database :
MEDLINE
Journal :
Vision research
Publication Type :
Academic Journal
Accession number :
8759469
Full Text :
https://doi.org/10.1016/0042-6989(95)00269-3