What is psychophysically perfect image stabilization? Do perfectly stabilized images always disappear?: comment.

This Communication calls attention to an earlier paper [L. E. Arend and G. T. Timberlake, J. Opt. Soc. Am. A 3, 235 (1986)] in which direct measurements have shown that retinal-image movements less than 1 arc min are required for perfect stabilization. It also cites papers that show that stabilized images of targets that contain no sharp structure in the foveal region disappear completely and permanently. Other targets disappear and reappear as a whole or as fragments intermittently.