What Causes People to See Tracers?

by C.K. Adams
Afterimages are often negative or inverted, leading to disturbing and confusing images.

Afterimages are often negative or inverted, leading to disturbing and confusing images.

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The human eye creates an image from multiple parts. However, the brain also contributes information to the images that the eye gathers. People who experience tracers suffer from palinopsia. A tracer is an afterimage that follows an object after the eye initially sees the image. These images are often disturbing as they appear to be hallucinations or ghostly negative images of the real picture. Although the problem may seem to be with the eye, the brain is actually responsible for this rare neurological disorder.

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Head Trauma

Although the skull protects the brain from most trauma, severe head trauma often causes vision problems, resulting in tracers. In one case report, a patient received head trauma from a motor vehicle accident, and, as a result, the patient began experience afterimages. The problem may result from improper blood flow or loss of brain matter around the amygdala, the part of the brain responsible for sight.

Brain Disorders

Palinopsia sufferers also have brain disorders with afterimage symptoms. Brain neoplasia, epilepsy, systemic disease and psychiatric illnesses create palinopsia symptoms. In extreme cases, patients see multiple negative image tracers. The persistence of this effect leads to depression and insomnia in patients with palinopsia.

Drug Use

Mind-altering drugs also lead to vision tracers. In one case report, a patient took large amounts of lysergic acid diethylamide or LSD. As a psychedelic drug, LSD produces strange visuals with eyes open or closed. Patients also report experiences with synesthesia, which stimulates a person's senses and leads to involuntary responses. Patients with a history of drug use can experience different brain illnesses after use, depending on the dosage and frequency.

Pathway Lesions

The brain has hundreds of pathways that carry information. However, suffers of palinopsia experience lesions along the posterior visual pathways. Lesions occur for a variety of reasons, from scarring to disease, hemorrhaging to concussions. Ophthalmologists recommend neuroimaging for palinopsia sufferers in the presence of a normal visual field who experience pathway lesions.

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