Abstract
Purpose: In the interocular suppression a stimulus presented in one eye is suppressed whereas a different stimulus in the other eye is perceived for a certain time interval. For strabismic observers the suppression continuously occurs between different retinal images made by misalignment of eye positions. It has been in question whether the strabismus suppression is different from the interocular suppression for normal observers. This issue would be important for a developmental aspect of the brain selectivity. In this research we compared contrast adaptation effects under interocular suppression for normal and strabismic observers. Methods: In the suppression condition, the vertical square-wave grating (3-deg diameter, 2.0 cpd, 100 % contrast, 42 cd/m^2 mean luminance) was presented in one eye as a dominant stimulus. The horizontal square-wave grating (3-deg diameter, 1.0∼2.5 cpd, contrast: 10 times greater than threshold) was presented in the other eye as an adaptation stimulus. After adaptation, the observer performed contrast matching between the adaptation stimulus and the matching grating of the same frequency. Results: We found that, for both types of observers, effects of contrast adaptation existed in the suppression and no suppression conditions although the contrast adaptation strength was different. Conclusions: These findings suggest that both for normal and strabismic observers the interocular suppression occurred at a site in the visual system after the locus of contrast adaptation.