Ghosting: The term 'ghosting' was coined around 1957, and originally referred to the false image on a TV screen, caused by signal reflection. The perceptual effects of LASIK are often similar, but here, signal reflection results from irregularities in the corneal surface. Ghosts vary in terms of transparency, size, and even the colors ghosted. Some patients see two images of equal or nearly equal opacity, technically referred to as "monocular diplopia," which literally means "one eye, two images." Other patients see multiple images, technically referred to as "monocular polyopia," which literally means "one eye, multiple images." Because tears fill in the hills and valleys of an irregular post-LASIK cornea, some patients complain that episodes of dry eye either cause one or more ghost images to emerge, or else excerbate ghosts which are always present to some degree post-LASIK. Some patients report that that their LASIK ghosts emerge only in dim light conditions. These patients are likely to have large pupils with corneal irregularies that become apparent only when the pupil expands. Because ghosts vary in terms of their "distance" from the "real image," patients whose ghosts are very close together may mistake ghosting for blurry vision.