Although it is known that stereo-acuity declines with increasing eccentricity of the targets, it is not clear how we use disparity information in the peripheral visual field for pattern perception. To examine this question, we investigated pattern perception by restricting the area that presented stereo or luminance information in the periphery. We measured the reaction time for recognising a letter defined by binocular disparity or by luminance in a random-dot display. We restricted the area containing the specific information (disparity or luminance) using an eye-contingent window technique. Disparity or luminance information was thus present only inside a window centred on the fixation point. Observers viewed the display with free eye movement. The magnitudes of the disparity and luminance contrast were chosen so as to give the same reaction times when the area containing the pattern information was not restricted. Eye movements were measured by a limbus-tracking system and the signal was fed into a computer for real-time control of the window position. The reaction time increased as the window size decreased. The increase in reaction time, however, was steeper for the stimuli defined by disparity than for the stimuli defined by luminance. We conclude that disparity information in the periphery is used for recognising a pattern and is more effective than luminance information for a given window size.