3% of children live with Amblyopia (‘lazy-eye’), a visual disorder where acuity in one eye is poor even with glasses on. Amblyopia includes (1) reduced sensitivity in the amblyopic eye, and (2) interocular suppression, whereby the good eye suppresses the amblyopic eye. Our goal was to develop a method to efficiently characterize both mechanisms. Participants viewed a Gabor stimulus modulating between 0-100% contrast over time through a stereoscope, that presented a different image to each eye. Participants reported perceived contrast over time using a joystick. On each trial, the initial 14 s consisted of binocularly identical gratings modulating at 1/7 Hz, followed by 48 s where the gratings modulated at 1/8 Hz in one eye, and 1/6 Hz in the other. Separately, we measured visual acuity, stereoacuity, contrast sensitivity, the interocular suppression ratio. This method was highly efficient: only 30 min of data were needed to estimate monocular sensitivity and interocular suppression. Another advantage of this approach is that the stimulus is relatively naturalistic – the images in the two eyes are the same, except for the difference in contrast. This is important due to the nature of its binocularity and naturalistic conditions, as this will be the first of its kind - allowing clinicians a better way to assess those with amblyopia.