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The Purkinje tree is an image of the retinal blood vessels in one's own eye, first described by Purkyně in 1823. It can be seen by shining the beam of a small bright light through the pupil from the periphery of a subject's vision. This results in an image of the light being focused on the periphery of the retina.
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 ...
Bright lights and blobs [11] Zigzag lines [12] Distortions in the size or shape of objects [13] Vibrating visual field; Scintillating scotoma. Shimmering, pulsating patches, often curved; Tunnel vision; Scotoma [14] Blind or dark spots; Curtain like effect over one eye; Slowly spreading spots; Kaleidoscope effects; Temporary blindness in one or ...
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The eye and brain "edit out" the shadow lines of the capillaries, partially by dark adaptation of the photoreceptors lying beneath the capillaries. The white blood cells, which are larger than red blood cells, but much rarer and do not absorb blue light, create gaps in the blood column, and these gaps appear as bright dots.
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 ...
Static and auras in vision, Palinopsia, Blue field entoptic phenomenon, Nyctalopia, Tinnitus: Complications: Poor quality of vision, Photophobia, Heliophobia, Depersonalization and Derealization [2] Usual onset: Visual Snow can appear at any time, but it commonly appears at birth, late teenage years, and early adulthood. Causes
The color of the iris itself is of virtually no importance for the red-eye effect. This is obvious because the red-eye effect is most apparent when photographing dark-adapted subjects, hence with fully dilated pupils. Photographs taken with infrared light through night vision devices always show very bright pupils because, in the dark, the ...