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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)
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). Phosphenes that are induced by movement or sound may be associated with optic neuritis. [1] [2]
Floaters suddenly appearing in the field of vision or a sudden increase in the number of floaters. Floaters may resemble cobwebs, specks of dust, or shapes such as ovals or circles; Flashes of light in vision ; Experiencing a "dark curtain" or shadow moving from the peripheral vision toward the central vision; Sudden blurred vision
Flash blindness is an either temporary or permanent visual impairment during and following exposure of a varying length of time to a light flash of extremely high intensity, such as a nuclear explosion, flash photograph, lightning strike, or extremely bright light, i.e. a searchlight, laser pointer, landing lights or ultraviolet light. [1]
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.
Vision remains normal beyond the borders of the expanding scotoma(s), with objects melting into the scotoma area background similarly to the physiological blind spot, which means that objects may be seen better by not looking directly at them in the early stages when the spot is in or near the center. The scotoma area may expand to occupy one ...
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. [ citation needed ] However, if visual snow becomes persistent and continuous — especially if it is accompanied by other symptoms, such as headaches, difficulty focusing, or intense visual ...
Apollo 17 astronaut Ron Evans wearing the ALFMED light-flash detector during the outbound flight from Earth During the Apollo 16 and Apollo 17 transits, astronauts conducted the Apollo Light Flash Moving Emulsion Detector (ALFMED) experiment where an astronaut wore a helmet designed to capture the tracks of cosmic ray particles to determine if ...