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Photopsia is the presence of perceived flashes of light in the field of vision. It is most commonly associated with: [4] posterior vitreous detachment; migraine aura (ocular migraine / retinal migraine) migraine aura without headache; scintillating scotoma; retinal break or detachment; occipital lobe infarction (similar to occipital stroke)
Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area. It typically affects both eyes, as it is not a problem specific to one eye. [5] [6] The affected area flickers but is not dark. It then gradually expands outward ...
Moore's lightning streaks are lightning type streaks (seen to the temporal side) due to sudden head or eye movement in the dark. They are generally caused by shock waves in the vitreous humor hitting the retina or traction on the retina from fibers in the vitreous humor.
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One example of a pressure phosphene is demonstrated by gently pressing the side of one's eye and observing a colored ring of light on the opposite side, as detailed by Isaac Newton. [ 7 ] [ 8 ] [ 9 ] Another common phosphene is "seeing stars" from a sneeze , laughter, a heavy and deep cough, blowing of the nose , a blow on the head or low blood ...
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.
This can occur in low-light conditions, in the dark, or when the visual system amplifies light perception. In these cases, visual snow is a normal reaction of the body, related to the way photoreceptors (rods) and neurons respond to weak or insufficient stimuli.
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.