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Orientation tuning and contrast dependence of continuous flash suppression in amblyopia and normal vision

Gao, Tina Y.; Ledgeway, Timothy; Lie, Alyssa L.; Anstice, Nicola; Black, Joanna; McGraw, Paul V.; Thompson, Benjamin


Tina Y. Gao

Alyssa L. Lie

Nicola Anstice

Joanna Black

Professor of Visual Neuroscience

Benjamin Thompson


Purpose: Suppression in amblyopia may be an unequal form of normal interocular suppression or a distinct pathophysiology. To explore this issue, we examined the orientation tuning and contrast dependence of continuous flash suppression (CFS) in adults with amblyopia and visually normal controls.

Methods: Nine patients (mean age, 26.9 ± SD 4.7 years) and 11 controls (mean age, 24.8 ± SD 5.3 years) participated. In the CFS paradigm, spatially one-dimensional noise refreshing at 10 Hz was displayed in one eye to induce suppression of the other eye, and suppression strength was measured by using a grating contrast increment detection task. In experiment 1, noise contrast was fixed and the orientation difference between the noise and the grating was varied. In experiment 2, noise and grating orientations were identical and noise contrast was varied.

Results: Suppression patterns varied in both groups. In experiment 1, controls showed consistently orientation-tuned CFS (mean half-height bandwidth, 35.8° ± SD 21.5°) with near-equal strength between eyes. Five of nine patients with amblyopia exhibited orientation-independent CFS. Eight patients had markedly unequal suppression between eyes. Experiment 2 found that increasing the noise contrast to the amblyopic eye may produce suppression of the fellow eye, but suppression remained unequal between eyes.

Conclusions: Our data revealed that orientation specificity in CFS was very broad or absent in some patients with amblyopia, which could not be predicted by clinical measures. Suppression was unbalanced across the entire contrast range for most patients. This suggests that abnormal early visual experience disrupts the development of interocular suppression mechanisms.


Gao, T. Y., Ledgeway, T., Lie, A. L., Anstice, N., Black, J., McGraw, P. V., & Thompson, B. (2018). Orientation tuning and contrast dependence of continuous flash suppression in amblyopia and normal vision. Investigative Ophthalmology & Visual Science, 59(13), 5462-5472.

Journal Article Type Article
Acceptance Date Oct 13, 2018
Online Publication Date Nov 19, 2018
Publication Date Nov 19, 2018
Deposit Date Nov 21, 2018
Publicly Available Date Nov 21, 2018
Journal Investigative Opthalmology & Visual Science
Print ISSN 0146-0404
Electronic ISSN 1552-5783
Publisher Association for Research in Vision and Ophthalmology
Peer Reviewed Peer Reviewed
Volume 59
Issue 13
Pages 5462-5472
Public URL
Publisher URL


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