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Chromostereopsis is a visual illusion whereby the impression of depth is conveyed in two-dimensional color images, usually of red–blue or red–green colors, but can also be perceived with red–grey or blue–grey images. [1] [2] Such illusions have been reported for over a century and have generally been attributed to some form of chromatic ...
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.
Fluorescence intermittency, or blinking, is the phenomenon of random switching between ON (bright) and OFF (dark) states of the emitter under its continuous excitation.It is a common property of the nanoscale emitters (molecular fluorophores, colloidal quantum dots) related to the competition between the radiative and non-radiative relaxation pathways.
In a technique known as blue field entoptoscopy, the effect is used to estimate the blood flow in the retinal capillaries.The patient is alternatingly shown blue light and a computer generated picture of moving dots; by adjusting the speed and density of these dots, the patient tries to match the computer generated picture to the perceived entoptic dots.
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. Presence of at least 2 additional visual symptoms of the 4 following categories: i. Palinopsia. At least 1 of the following: afterimages or trailing of moving objects. ii.
Fig.1 Surround Suppression Demo. With eyes fixed on the blue square, the center of the circle on the right appears to be lower contrast than the circle on the left, even though they are physically identical. Visual processing abnormalities in schizophrenia are commonly found, and contribute to poor social function. [1]
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 ]
Vision loss in toxic and nutritional optic neuropathy is bilateral, symmetric, painless, gradual, and progressive. Dyschromatopsia, a change in color vision, is often the first symptom. Some patients notice that certain colors, particularly red, are less bright or vivid; others have a general loss of color perception.