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I present the results of two experiments that investigated the role of central and peripheral vision in collision detection and control of braking. Displays simulated observer movement over a ground plane toward obstacles in the observer's path (Experiment 1) or toward a vertical 2-D plane (Experiment 2). Optical expansion was depicted under the constraint that tau-dot remains constant throughout the approach. Furthermore, displays were masked centrally (peripheral vision) or peripherally (central vision) with mask size ranging from 10° to 30° in diameter in steps of 5°. Results demonstrated that the peripheral retina is more effective than the central retina in processing the optic flow pattern specifying tau-dot and thus collision detection. Previous research demonstrated either minimal difference or a slight advantage to central vision in the capacity to process the self-motion information about heading and postural control. Those results conflicted with clinical studies showing that patients with peripheral-vision loss experience more problems maintaining safe mobility than those with central vision loss. The present results are more consistent with clinical findings. It appears then that the roles played by retinal center and periphery differ depending on the type of self-motion they subserve.