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Photopsias is defined as an effect on the vision that causes appearances of anomalies in the vision. Photopsias usually appear as: flickering lights; shimmering lights; floating shapes; moving dots; snow or static; Photopsias are not generally a condition on their own, but a symptom of another condition.
Most vision researchers believe that phosphenes result from the normal activity of the visual system after stimulation of one of its parts from some stimulus other than light. For example, Grüsser et al. showed that pressure on the eye results in activation of retinal ganglion cells in a similar way to activation by light. [ 23 ]
Visual snow is a phenomenon where a person perceives visual disturbances, such as fine graininess or "static," in their field of vision. This can occur in low-light conditions, in the dark, or when the visual system amplifies light perception.
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 ...
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.
Eye flashing: characterised by bursts or streaks of light that appear in an individual's field of vision. As eye flashing may indicate impending retinal detachment, medical attention is required. [8] Eyelid twitching: where the eyelid muscles contract in an irregular or abnormal pattern. Such movements can cause irritation and fatigue to the ...
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.
Vitreous hemorrhage is diagnosed by identifying symptoms, examining the eye, and performing tests to identify the cause. Some common tests include: Examination of the eye with a microscope; Pupil dilation and examination; An ultrasound examination may be used if the doctor does not have a clear view of the back of the eye