entoptic phenomenon


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.