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Visual auras can be simple or complex. Simple visual symptoms can include static, flashing, or moving lights/shapes/colors caused mostly by abnormal activity in the primary visual cortex. Complex visual auras can include people, scenes, and objects which results from stimulation of the temporo-occipital junction and is lateralized to one hemifield.
Scintillating scotoma is a common visual aura that was first described by 19th-century physician Hubert Airy (1838–1903). Originating from the brain, it may precede a migraine headache , but can also occur acephalgically (without headache), also known as visual migraine or migraine aura. [ 4 ]
Visual snow as a temporary occurrence under certain conditions is normal and doesn't require intervention. [citation needed] Visual snow syndrome is a pathological condition, where visual disturbances persist constantly and may be caused by issues in the visual or nervous system, requiring medical attention. [citation needed]
Photopsia; This is an approximation of the zig-zag visual of a scintillating scotoma as a migraine aura. It moves and vibrates, expanding and slowly fading away over the course of about 20 minutes.
A visual hallucination is a vivid visual experience ... presenting as classic auras or less common manifestations like ... An example of this would be hallucinations ...
Illusory palinopsia is often worse with high stimulus intensity and contrast ratio in a dark adapted state.Multiple types of illusory palinopsia often co-exist in a patient and occur with other diffuse, persistent illusory symptoms such as halos around objects, dysmetropsia (micropsia, macropsia, pelopsia, or teleopsia), Alice in Wonderland Syndrome, visual snow, and oscillopsia.
Scintillating scotoma is a common visual aura in migraine. [4] Less common, but important because they are sometimes reversible or curable by surgery , are scotomata due to tumors such as those arising from the pituitary gland , which may compress the optic nerve or interfere with its blood supply.
Hence, they are different from optical illusions, which are caused by the visual system and characterized by a visual percept that (loosely said) appears to differ from reality. Because entoptic images are caused by phenomena within the observer's own eye, they share one feature with optical illusions and hallucinations: the observer cannot ...