Derived from the Greek word “palin” for “again” and “opsia” for “seeing,” palinopsia is a rare visual system processing distortion. People with this distortion continue to see the image of an object they were looking at even after they’ve stopped looking at it.
Palinopsia shouldn’t be confused with physiological afterimage. Physiological afterimage is a normal response that occurs when an image briefly persists after looking away, such as following a camera flash.
According to the American Academy of Ophthalmology (AAO), there are some marked differences between palinopsia and physiological afterimage:
|positive images (the same colors as the original image)||negative images (complementary colors of the original image)|
|images may appear immediately or following a time interval||images appear immediately|
|images are long lasting or intense||images are brief|
The two general categories for palinopsia are hallucinatory palinopsia and illusory palinopsia.
People with hallucinatory palinopsia see images that:
- occur anywhere within the visual field
- are high resolution
- are long lasting
Hallucinatory palinopsia could also include action, as opposed to a static image. The action scene is continuously replayed.
People with illusory palinopsia see images that:
- are affected by immediate environmental factors, such as light and motion
- are low resolution
- are short lasting
Illusory palinopsia may also include:
- Visual trailing. Multiple images appear to travel behind a moving object.
- Light streaking. A streak of images is seen, typically when looking at a bright object against a dark background.
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Palinopsia may also be idiopathic. This means it’s a spontaneous condition with an unknown cause.
According to the AAO, hallucinatory palinopsia is associated with visual memory dysfunction. Seizures or lesions in the brain (posterior cortical) can cause it.
Seizures associated with hallucinatory palinopsia are linked with metabolic imbalances, such as:
- carnitine deficiency
- Creutzfeldt-Jakob disease
- high blood sugar
- ion channel disturbances
Lesions in the brain associated with hallucinatory palinopsia include:
- arteriovenous malformations
- tissue death from poor blood supply (infarctions)
- new abnormal growth of tissue (neoplasms)
- tuberculomas, or tumor-like growths related to tuberculosis
According to the AAO, illusory palinopsia is associated with visual distortions caused by environmental (external) factors, such as:
- changes in neurotransmitter receptors associated with migraine
- hallucinogen persisting perception disorder (HPPD)
- trauma to the head
- medications and drugs
Medications that may cause illusory palinopsia include:
Diagnosis starts with a physical exam and a full history of brain and eye health. This includes neuroimaging and visual field testing.
Depending on the results from the initial steps in the diagnosis, your doctor may recommend a differential diagnosis. They may test for:
- toxins from drugs
- metabolic conditions, like high blood sugar
- mental health conditions, including depression and schizophrenia
- structural cerebral lesions
Treatment for hallucinatory and illusory palinopsia treats the underlying cause, such as treating seizures, lesions, or migraine.
Other treatments for illusory palinopsia may include:
- medications that decrease neuron excitability, such as acetazolamide, clonidine, or gabapentin
- tinted lenses and sunglasses
- alternative prescriptions, if medications are causing palinopsia
If an image you were looking at persists after you stop looking at it, you could be experiencing palinopsia.
Because it’s a relatively rare condition, it’s difficult to pinpoint its cause. It may have multiple causes.
For a full diagnosis to determine whether you have illusory or hallucinatory palinopsia, your doctor may refer you to a neuro-ophthalmologist. Once the cause of your palinopsia is determined, they can tailor a treatment plan to your specific needs.