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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] Vitreous shrinkage or liquefaction, which is the most common cause of photopsia, causes a pull in vitreoretinal attachments, irritating the retina and causing it to discharge electrical impulses.
Blepharospasm is often associated with dry eyes, but the causal mechanism is still not clear. [16] [8] Research in New York and Italy suggests that increased blinking (which may be triggered by dry eyes) leads to blepharospasm. [24] [25] A case control study in China found that blepharospasm aggravated dry eyes. [26]
Photosensitive epilepsy. Photosensitive epilepsy ( PSE) is a form of epilepsy in which seizures are triggered by visual stimuli that form patterns in time or space, such as flashing lights; bold, regular patterns; or regular moving patterns. PSE affects approximately one in 4,000 people (5% of those with epilepsy). [ 1]
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 ...
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.
The corneal reflex, also known as the blink reflex or eyelid reflex, [ 1] is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), though it could result from any peripheral stimulus. Stimulation should elicit both a direct and consensual response (response of the opposite eye).
Entoptic phenomena (from Ancient Greek ἐντός (entós) 'within' and ὀπτικός (optikós) 'visual') are visual effects whose source is within the human eye itself. (Occasionally, these are called entopic phenomena, which is probably a typographical mistake.) In Helmholtz 's words: "Under suitable conditions light falling on the eye ...
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