What is Palinopsia?
Palinopsia is a visual disturbance that causes images to persist to some extent even after their corresponding stimulus has left. These images are known as afterimages and occur in persons with normal vision. However, a person with palinopsia experiences them to a significantly greater degree, to the point where they become difficult or impossible to ignore.
Further description: Palinopsia Described by Vision Scientist at University of Wisconsin–Madison
What causes Palinopsia?
Palinopsia sometimes appears on its own, but is more often accompanied by other visual disturbances such as visual snow, and can be attributed to a number of conditions affecting the brain including, but not limited to, medications, seizure disorders, tumors, occiptal lobe or visual pathway lesions, sub-cortical hemorrhage, and dural arteriovenous malformations. It can also sometimes present in otherwise healthy individuals.
The pathology which leads to palinopsia can occur through several pathways, which makes teasing out the source of a patient’s palinopsia difficult. Though normal negative afterimages are generally understood to be a retinal phenomenon, palinopsia is thought to be a brain-related disorder, and not an eye-related disorder. This is likely because palinopsia is most commonly encountered in connection with diseases, drugs or injuries which affect the brain.