Other Depth Cues
1. Focusing Accommodation
The lenses in our eyes must change thickness when trying to focus on objects at different depths. (Some authors describe this as a monocular cue; others as a binocular cue; and still others describe it as neither.)
In the image at the top of this page, the lens is thin allowing the more distant object to come into focus on the back of the eye. Meanwhile, the nearer object will be perceived as blurry.
The opposite situation is shown in the lower image. Here the thicker lens allows the nearer object to be perceived sharp and clear while the farther object appears blurry.
