Is second-order spatial loss in amblyopia explained by the loss of first-order spatial input?
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Updated: Oct 3, 2026

The Measurement and Treatment of Suppression in Amblyopia
Published on: December 14, 2012
E H Wong1, D M Levi, P V McGraw
1University of Houston, College of Optometry, The University Eye Institute, 4901 Calhoun Blvd, Houston, TX 77204-6052, USA. ewong@bayou.uh.edu
Abstract:
The purpose of the study was to determine whether amblyopes show detection loss for second-order spatial information, and if present, whether the loss is explained by the loss of first-order spatial input. We psychophysically determined detection thresholds for the amblyopic and non-amblyopic eyes of five adult amblyopes and the dominant eyes of three control observers. We found that four amblyopic eyes and two non-amblyopic eyes showed second-order loss relative to the control eyes. The second-order loss was greater than the first-order loss at the carrier spatial frequency (first-order input). The extra second-order loss indicates an early amplification of cortical neural loss that we speculate is due to deficient binocular input to second-order neurons.
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