Purchase this article with an account.
Carmen Pons, Reece Mazade, Jianzhong Jin, Mitchell Dul, Qasim Zaidi, Jose-Manuel Alonso; Visual dominance for darks increases in amblyopia.. Journal of Vision 2018;18(10):539. doi: 10.1167/18.10.539.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
We have previously shown that luminance/response saturation in visual cortex is more pronounced for luminance increments (ON responses) than decrements (OFF responses) (Kremkow et al., 2014). Moreover, we showed that the pronounced ON luminance/response saturation causes an enlargement of light stimuli and enhances neuronal size suppression, making visual responses at low spatial frequencies weaker for lights than darks (Pons et al., 2016). Because optical blur reduces high spatial frequencies in the image, it should affect more the visual salience of lights than darks. Therefore, if optical blur is present during brain development, it should make cortical responses more dark dominated. To test our hypothesis, we measured the visual salience for light and dark stimulus in 19 amblyopic adults that experienced sustained optical blur early in life. Consistent with our hypothesis, we found that amblyopic subjects were more accurate and faster at detecting dark than light squares on a noisy background (Komban et al., 2011) and that the advantage for darks was more pronounced in the amblyopic eye than in the fellow eye (average dark-light difference in percent correct, amblyopic: 14.69±2.63 vs fellow: 2.81±0.67%, p < 0.001; reaction time, amblyopic: 1.82±0.29 vs fellow: 1.35±0.15 sec, p=0.03; two-sided Wilcoxon tests, n=19 subjects). Moreover, the differences between amblyopic and fellow eyes in dark dominance were strongly correlated with the severity of amblyopia (R2=0.8, p < 0.001). Performance in the visual acuity task was also lower for lights than darks in the amblyopic eye, but unlike the results for the visual salience task, the difference was not significantly larger than in the fellow eye (average dark-light accuracy difference, amblyopic: 17.37±3.12 vs fellow: 13.63±3.95%, p=0.77, two-sided Wilcoxon test, n=7 subjects). These results confirm our prediction that dark dominance for visual salience is increased in amblyopia and that sustained optical blur affects ON/OFF response balance during brain development.
Meeting abstract presented at VSS 2018
This PDF is available to Subscribers Only