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Avital Moshkovitz, Inbal Ziv, Maria Lev, Uri Polat; Spatial and Temporal Visual Perception of Infantile Nystagmus. Journal of Vision 2019;19(10):160. doi: https://doi.org/10.1167/19.10.160.
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© ARVO (1962-2015); The Authors (2016-present)
Background: Infantile nystagmus (IN) is a form of spontaneous oscillation of the eyes, which results in excessive motion of images on the retina, accompanied by poor vision including reduction in visual acuity (VA) and contrast sensitivity (CS). The aim of the present work was to investigate the underlying mechanism of the deteriorated visual performance, which is still poorly understood. Methods: Contrast detection for Gabor patch was measured in ten IN and ten normally sighted subjects at a viewing distance of 60 cm and target presentation durations of 60, 120, 240, 320 and 480 ms under monocular and binocular conditions. The spatial frequencies of the Gabors were adjusted to be slightly lower than the cutoff threshold of each subject (IN~3 cpd; controls=9 cpd). Results: Differences in the VA between the eyes in IN were less than one line (0.1 logMar, p< 0.05), showing no amblyopia. Better or poor eyes were categorized based on the VA. Statistically significant differences (p< 0.001) were found between the CS of poor and better eyes for IN but not for the control subjects. The critical durations for the IN was significantly slower than the controls: binocular (369 vs 196), better eye (389 vs 250), poor eye (470 vs 294ms). The critical durations of the better and both eyes were similar highlighting the lack of binocular summation in IN. Finally, no significant differences were observed between the fixation abilities of the poor and better eyes. Conclusions: The observed significant differences in CS between eyes and the longer CD in the poor eye have similar features as in amblyopia. The patterns of eye movements of both eyes in IN are similar suggesting that the underlying cause of the perceptual impairment is due to abnormal cortical developmental of IN subjects rather than an ocular mechanism.
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