Abstract

Normal and low-vision observers judged the relative depths of three nonoccluding vertical cylinders (low vision: the inability to read newsprint at a normal reading distance). The featureless cylinders, appearing as white stripes, varied unpredictably in width between trials. Monocular discriminations of depth were made in two tasks: (1) a target cylinder was located relative to the common plane of the remaining two, and (2) the cylinders were uniquely ordered in depth. Observers made judgments without head motion and then following free horizontal head translations. Normal observers performed indistinguishably from low-vision observers for judgments made without head motion for both tasks. Normal observers improved to near perfect depth discrimination for judgments made following head translation in both tasks while the performance of low-vision observers was unchanged within each task. The error judgments of normal observers making head translations showed reduced reliance on the uninformative size cue in both tasks. The depth errors of low-vision observers making head translations showed a maintained reliance on spurious size cues.

© 1991 Optical Society of America