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Visual snow: dynamic, continuous, tiny dots observed across the entire visual field at any time of the day, regardless of lighting conditions, persisting for more than three months. The dots are usually black/gray on a white background and gray/white on a black background; however, they can also be transparent, white flashing, or colored.
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 ...
A scotoma may include and enlarge the normal blind spot. Even a small scotoma that happens to affect central or macular vision will produce a severe visual disability, whereas a large scotoma in the more peripheral part of a visual field may go unnoticed by the bearer because of the normal reduced optical resolution in the peripheral visual field.
Distribution of rods and cones along a line passing through the fovea and the blind spot of a human eye [1]. A blind spot, scotoma, is an obscuration of the visual field.A particular blind spot known as the physiological blind spot, "blind point", or punctum caecum in medical literature, is the place in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the ...
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.
Classical image of the shape and size of the visual field [28]. The outer boundaries of peripheral vision correspond to the boundaries of the visual field as a whole. For a single eye, the extent of the visual field can be (roughly) defined in terms of four angles, each measured from the fixation point, i.e., the point at which one's gaze is directed.
Isolation tank – Pitch-black, light-proof, soundproof environment heated to the same temperature as the skin; Prisoner's cinema – Visual phenomenon involving seeing animated lights in the darkness; Scintillating scotoma – Visual aura associated with migraine; Photopsia – Presence of perceived flashes of light in one's field of vision
An example of the scintillating grid illusion. Dark dots seem to appear and disappear at intersections. The scintillating grid illusion is an optical illusion, discovered by E. and B. Lingelbach and M. Schrauf in 1994. [2] It is often considered a variation of the Hermann grid illusion but possesses different properties. [2] [3]