Stereopsis nay occur m the presence of large disparities despite the fact that double images are visible. Many theorists have proposed that neural fusion of the diplopic half-images produces the depth effect even though the neural fusion is not accompanied by phenomenal fusion. This paper offers the alter-native explanation that stimuli containing widely disparate half-images are compound Panum-limiting case stereograms. It is shown depth may be controlled by controlling disparity of fixation in both simple and compound limiting case stereograms. It is concluded that widely disparate half-images do not interact in the computation of depth.