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Closed-eye hallucinations and closed-eye visualizations (CEV) are hallucinations that occur when one's eyes are closed or when one is in a darkened room. They should not be confused with phosphenes , perceived light and shapes when pressure is applied to the eye's retina, or some other non-visual external cause stimulates the eye.
Peripheral (posterior) vitreous detachment occurs when the gel around the eye separates from the retina. This can naturally occur with age. However, if it occurs too rapidly, it can cause photopsia which manifests in flashes and floaters in the vision. Typically, the flashes and floaters go away in a few months.
Flashing lights (such as strobe lights) or rapidly changing or alternating images (as in clubs, around emergency vehicles, near overhead fans, in action movies or television programs, etc.) are examples of patterns in time that can trigger seizures, and these are the most common triggers. Static spatial patterns such as stripes and squares may ...
Flicker vertigo, sometimes called the Bucha effect, is "an imbalance in brain-cell activity caused by exposure to low-frequency flickering (or flashing) of a relatively bright light." [1] It is a disorientation-, vertigo-, and nausea-inducing effect of a strobe light flashing at 1 Hz to 20 Hz, approximately the frequency of human brainwaves.
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.
A phosphene is the perception of light without light actually entering the eye, for instance caused by pressure applied to the closed eyes. A phenomenon that could be entoptical if the eyelashes are considered to be part of the eye is seeing light diffracted through the eyelashes.
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An artist's representation of how some people may see phosphenes by retinal stimulation. A phosphene is the phenomenon of seeing light without light entering the eye.The word phosphene comes from the Greek words phos (light) and phainein (to show).