[website] Blue field entoptic phenomenon

[jinnantonnixx]

Huh?

 

I read about blue field entoptic phenomenon a while ago.

 

I was at a loose end today so I took advantage of today's deep blue sky to see if I could see it. It's really quite remarkable, more so if you put your finger on your pulse and observe the motion of the 'sprites' in time with your pulse. You're actually watching your own white blood cells pulsing through your eye's capillaries.

 

 

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. The dots are short-lived, visible for a second or less, and traveling short distances along seemingly random, curvy paths. Some of them follow the same path as predecessors. The dots may be elongated along the path like tiny worms. The speed of the dots varies in sync with the pulse, they briefly accelerate at each heart beat. The dots appear in the central field of view, within 10 to 15 degrees from the fixation point. The left and right eye see different dots; someone looking with both eyes sees a mixture.

 

The dots are white blood cells moving in the capillaries in front of the retina of the eye. Blue light (optimal wavelength: 430 nm) is absorbed by the red blood cells that fill the capillaries. 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 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.

 

 

Next time you see a deep blue sky, try it.

 

Blue field entoptic phenomenon (or sky sprites) are mentioned 2 minutes into the video.

Edited May 28, 2016 by jinnantonnixx