Palinopsia

Palinopsia (Greek: palin for "again" and opsia for "seeing") is a visual disturbance that causes images to persist even after their corresponding stimulus has left. It is similar to an afterimageseen after looking into a bright light, but in palinopsia, color inversion is rare. Also, intensity and stimulus duration have no influence on the persistence of images in palinopsia, which is in sharp contrast with afterimages.

Persistent palinopsia can be caused by vascular disease, a brain tumour, prescription medication, substance abuse (most notably LSD) or head trauma. Palinopsia can occur years after the last drug usage, either by itself or as part of a syndrome called HPPD.

Some people suffering from ocular migraineor, rarely, occipital lobe epilepsy, can also have bouts of palinopsia.

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Palinopsia Wikipedia article Palinopsia.