A simple reaction time paradigm was used to study binocular interactions for suprathreshold grating patterns before and after 8 days of constant monocular occlusion. Prior to patching, subjects demonstrated binocular summation for near threshold contrast stimuli and binocular summation and facilitation for high contrast stimuli. After the period of occlusion, the subjects showed binocular inhibition for high contrast stimuli but still demonstrated binocular summation for low contrast stimuli. The effects of occlusion were reversible and appear to be related to an oculomotor imbalance.