Reconsider the blood cell visualization thing. I've had bilateral PVD. Each was accompanied by an initial few minutes of seeing a few dozen small dark spots that had lighter grey centers. Most visible when I looked at the sky. They all disappeared after a few minutes. I think these were RBCs from minimal retinal blood vessel tearing at the PVD events.

Human RBCs are ~6µm - 8µm diameter. Human retinal light sensing cells range from ~0.5µm - 10µm diameter, depending on type and position. They're close packed.

Given the geometry, RBCs leaking onto retinal cells should cast shadows that could be resolved as images. And that's right where leakage is most likely to occur during a PVD event.

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ggm a day ago | parent | next [-]

Interesting. I told the specialist what I'd seen, they said "not blood cells" but I'm open to re-consideration. I got a pretty complete ocular examination both times, the iris dilation and "I must be a vampire I cannot handle sunlight" is a joy.

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BuyMyBitcoins a day ago | parent [-]

Floaters? https://en.wikipedia.org/wiki/Floater

	▲	ggm a day ago \| parent [-]
		No, quite different. Floaters look like paramecium in my visual field, or hairs floating in fluid (that kind of corona around an object) Maybe there is a sub class of floater which is like PVD but .. to me at least this was qualitatively different. I suppose the crap left over from a PVD incident would be a sub-class of "floater" but in quality, its nothing like the floaters I get "all the time" as normal life, before and after PVD. The one upside of PVD is I am told your chances of a retinal tear are reduced, if you have a "clean" PVD.

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jaggederest a day ago | parent | prev [-]

Slightly off topic, but on a clear blue sky it's possible to directly visualize the white blood cells running around on your retina. I love watching them go about business, and I think I heard it can even be used diagnostically to do a manual WBC count in extremis for leukoproliferative disease.

They're pretty tiny though, I'm not sure if you'd actually see a center in the RBCs

	▲	ridgeguy 17 hours ago \| parent [-]
		The lighter centers could have been diffraction around the object and reconvergence. Or some kind of signal processing effect at the retinal level. The retinal vessel network is a fun thing to inspect as you say. It works best for me when the sun is high in the sky. The bright, featureless blue brings out the branching network very well.