entoptic phenomenon


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entoptic phenomenon

A visual phenomenon arising from within the eye, marked by the perception of floating bodies, circles of light, black spots, and transient flashes of light. It may be due to the individual's own blood cells moving through the retinal vessels, or to floaters, which are small specks of tissue floating in the vitreous fluid. See: Moore lightning streaks; muscae volitantes; photopsia

Individuals may see imperfections of their own cornea, lens, and vitreous by looking at a white background through a pinhole held about 17 mm (4.3 in) from the eye. The person sees a patch of light the size of which varies with the diameter of the pupil. The abnormalities are seen as shadows or bright areas. This method can be used also to see early discrete lens opacities.

References in periodicals archive ?
This entoptic phenomenon, known as Haidinger's brush, was first described in the mid-1900s and is believed to be caused by xanthophyll pigments in the macular: lutein, zeaxanthin, and meso-zeaxanthin.
Perhaps the most commonly observed entoptic phenomenon is floaters, otherwise known as 'muscae volitantes' or 'flying gnats'.
This type of entoptic phenomenon may also be classified as phosphenes (see later).