Red blood cells pile up behind the white blood cell, showing up like a dark tail. The gaps are elongated because a spherical white blood cell is too wide for the capillary. The white blood cells, which are much rarer than the red ones and do not absorb blue light, create gaps in the blood column, and these gaps appear as bright dots. The eye and brain "edit out" the shadow lines of the capillaries, partially by dark adaptation of the photoreceptors lying beneath the capillaries. Blue light (optimal wavelength: 430 nm) is absorbed by the red blood cells that fill the capillaries. The dots are white blood cells moving in the capillaries in front of the retina of the eye. The dots are highly conspicuous against a monochromatic blue background (~430 nm) instead of the sky. Most people are able to see this phenomenon in the sky, although it is rather weak, and many people do not notice it until asked to pay attention. Difference from other entoptic phenomena.The left and right eye see different dots someone looking with both eyes sees a mixture. The dots appear in the central field of view, within 10 to 15 degrees from the fixation point. The speed of the dots varies in sync with the pulse they briefly accelerate at each heart beat. The dots may be elongated along the path like tiny worms. Some of them follow the same path as predecessors. The dots are short-lived, visible for a second or less, and traveling short distances along seemingly random, curvy paths. The blue field entoptic phenomenon or Scheerer's phenomenon (after the German ophthalmologist Richard Scheerer, who first drew clinical attention to it in 1924) is the appearance of tiny bright dots (nicknamed blue-sky sprites) moving quickly along squiggly lines in the visual field, especially when looking into bright blue light such as the sky.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |