Contents:
- Medical Video: Eye Floaters and Flashes, Animation.
- What is palinopsia?
- Get to know the types of palinopsia
- Various symptoms of palinopsia are based on the type
- What causes us to see palinopsia silhouettes?
- What checks should be done?
Medical Video: Eye Floaters and Flashes, Animation.
Shadows appear when light is blocked by an object. Try to stand back to the sun. So, your silhouette will fall right in front of your body. When you move away from the light, your shadows will shrink and disappear. But if you still see black shadows even after the object blocking the light source has moved away, you must be vigilant. No, suddenly seeing a black shadow does not mean you see a ghost. This can be a sign of a medical condition called palinopsia.
What is palinopsia?
Palinopsia is a term to describe a visual disorder characterized by the appearance of a visual illusion, causing a person to see a black shadow continuously or repeatedly for several minutes after the actual object disappears.
The term palinopsia is rooted in Ancient Greek which means "see again" ("palin"Which means" again "and"officer ” which means seeing).
Get to know the types of palinopsia
Palinopsia can be divided into two types, based on the condition experienced. The first is hallucinatory palinopsia which is characterized by a visual illusion formed, can be simple (light, line, color) or complex (animals, objects, humans), without any influence from the surrounding environment, usually occurs in high resolution. For example, after seeing a cat, the cat's silhouette that was previously "stuck" in your field of view.
Illusion of hallucinations is usually temporary and only a few seconds to a few minutes short). But in some cases the black shadow may last for hours. This type of palinopsia is also called afterimage.
The second type is palinopsia ilusori. Illusory palinopsia is the formation of a visual image with a form that is usually imperfect and in low resolution. The onset of this type of palinopsia is related to movement and light in the surrounding environment. That's why people who experience palinopsia ilusori can see flashes of a comet-like tail behind moving objects leaving light.
Illusory palinopsia is caused by abnormalities in how the eye forms the initial perception of an object. Meanwhile, palinopsia hallucinations are caused by abnormalities after the object is recorded in visual memory.
Various symptoms of palinopsia are based on the type
There are several forms of symptoms that can be complained about, including:
- Seeing black shadows that remain in the field of vision. The image of the object is the same as the original object that has been seen before, including the clarity, color, and resolution. So, the choir is not necessarily always a black shadow. It could be a duplicate of someone or object that we saw, like a hologram.
- A recurring scene for several minutes. For example, if someone sees a scene combing his hair, a few moments later he will be able to see the scene again when his vision has shifted. This can happen repeatedly.
- Categorical incorporation, that is when object A appears to overwrite other objects around it. Suppose someone sees a mustache in person A, he will see the same mustache for every other person around him.
- The line that appears behind the light and stays for a few seconds before finally disappearing. This causes difficulty in driving a car especially at night.
- Visual footprint, which is when the same object follows the object in front of it that is moving. Generally the image of objects seen will have the same shape and size, but with a lower color intensity. This is often described as "The Matrix”.
What causes us to see palinopsia silhouettes?
Palinopsia can arise due to a variety of things, ranging from dangerous diseases to the consequences of using certain drugs. Therefore, seeing black shadows (especially if they occur repeatedly) cannot be underestimated, let alone considered a mystical thing.
Some causes of palinopsia include:
- Brain tumor
- Disorders of arterivene blood vessel formation
- Epilepsy
- Early symptoms of stroke
- Severe impact on the head area that injures the brain (cerebral infarction, abscess)
- Migraine
- Drugs (trazodone, topiramat, ecstasy, and LSD)
What checks should be done?
Various types of examinations must be done to ascertain the cause of the onset of palinopsia. Examination that will be carried out depends on the complaints and also the possibility of the disease suffered.
Ophthalmologists generally will begin the examination by examining visual acuity, eyeball movements, examining the field of vision, and checking the condition of the front chambers.
Other advanced examinations such as neurological imaging using MRI, blood tests, electroencephalogram (EEG), and screening for drug use will be carried out according to the instructions obtained from the initial examination.
