# Am I seeing my blood flow? **URL:** \ **Category:** Factual Questions\ **Created:** [December 24, 2002, 6:37pm UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749 "2002-12-24T18:37:32Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![GuanoLad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guanolad/32/42_2.png) [@GuanoLad](https://boards.straightdope.com/u/GuanoLad)\ **Post date:** [December 26, 2002, 8:43am UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/21 "2002-12-26T08:43:12Z")
> [@](#): > > \*Originally posted by bbeaty \* > **and I also see the hundreds of moving white specks all over my visual field** When I first saw those, I immediately figured that they were the “stars” people see when they get knocked about. Not like in cartoons wwhere you hear a tweet tweet and a circle of five-pointed stars revolves around your head - but tiny moving points of bright white that look like the stars in the sky. ---
**Author:** ![drachillix](https://avatars.discourse-cdn.com/v4/letter/d/48db29/32.png) [@drachillix](https://boards.straightdope.com/u/drachillix)\ **Post date:** [January 22, 2003, 12:39am UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/22 "2003-01-22T00:39:55Z")
> [@](#): > > \*Originally posted by SpoilerVirgin \* > I don’t wear contacts, and for obvious reasons I do have to be wearing my glasses at all times, so either **drachillix** confused me with someone else, or was so overwhelmed by my cuteness that he failed to notice the specs. Maybe I need new glasses :eek: :smack: You were only like 5 feet away. Damn? How did I miss that. Must of been the cuteness. ---
**Author:** ![Pragmus](https://avatars.discourse-cdn.com/v4/letter/p/ac91a4/32.png) [@Pragmus](https://boards.straightdope.com/u/Pragmus)\ **Post date:** [April 27, 2011, 5:05pm UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/23 "2011-04-27T17:05:25Z")
I saw so many people posting replies to this question that had no idea what they were talking about that I had to create an account on here just to set the record straight. Yes, a direct light source on someone’s eyelid who is that nearsighted will produce a silhouette of the blood vessels and, in fact, will show a very clear picture of the blood cells going through even capillaries. This phenomenon can be experienced by people with normal eyesight as well by having sunlight exposed straight on to the closed eye in the morning before waking up. The lens is in a perfectly relaxed state when the person becomes conscious and if they don’t move and just lay there for a moment while the sun shines on them (we’ve all laid there in a lucid state during those first few minutes of waking up) you can see the red blood cells coursing through your capillaries, one cell at a time. So to the people who thought this guy gave a retardedly poor description of a floater and thought he was an idiot, consider that you indeed are merely mortal and that it is possible that some people you encounter online have knowledge you do not yourself posses. And, to the people who think that this phenomenon described is actually seeing the blood vessels on your retina, you are wrong. The “seeing stars” theory does involve blood flow and blood pressure inside the retina’s capillaries, but these two phenomena are unrelated apart from them taking place around the eye and involving blood flow. ---
**Author:** ![VinylTurnip](https://avatars.discourse-cdn.com/v4/letter/v/b2d939/32.png) [@VinylTurnip](https://boards.straightdope.com/u/VinylTurnip)\ **Post date:** [April 27, 2011, 5:31pm UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/24 "2011-04-27T17:31:14Z")
> [@Pragmus](#): > > So to the people who thought this guy gave a retardedly poor description of a floater and thought he was an idiot, consider that you indeed are merely mortal and that it is possible that some people you encounter online have knowledge you do not yourself posses. Welcome to the board. Who the hell are you talking to? ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [April 27, 2011, 5:39pm UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/25 "2011-04-27T17:39:40Z")
> [@VinylTurnip](#): > > Welcome to the board. Who the hell are you talking to? And also realized that whoever you are talking to, they posted to this thread approximately 8 years ago. ---
**Author:** ![StarvingButStrong](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/starvingbutstrong/32/335_2.png) [@StarvingButStrong](https://boards.straightdope.com/u/StarvingButStrong)\ **Post date:** [April 27, 2011, 7:35pm UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/26 "2011-04-27T19:35:34Z")
> [@Pragmus](#): > > I saw so many people posting replies to this question that had no idea what they were talking about that I had to create an account on here just to set the record straight. Yes, a direct light source on someone’s eyelid who is that nearsighted will produce a silhouette of the blood vessels and, in fact, will show a very clear picture of the blood cells going through even capillaries. . AHA! I am VINDICATED! Wahooo! Yeah, even if it is eight years later – I’ll take my victories where I can find them. Besides, revenge is a dish best served cold and all that. 😃 ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [April 27, 2011, 11:33pm UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/27 "2011-04-27T23:33:11Z")
I’ve seen this too and came to the conclusion that it must be capillaries. A bright light won’t work for me though, it needs to be the sky. Apparently they absorb blue light well. ---
**Author:** ![chorpler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chorpler/32/2888_2.png) [@chorpler](https://boards.straightdope.com/u/chorpler)\ **Post date:** [April 27, 2011, 11:40pm UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/28 "2011-04-27T23:40:56Z")
> [@Pragmus](#): > > And, to the people who think that this phenomenon described is actually seeing the blood vessels on your retina, you are wrong. The “seeing stars” theory does involve blood flow and blood pressure inside the retina’s capillaries, but these two phenomena are unrelated apart from them taking place around the eye and involving blood flow. You can see some interesting effects involving retinal blood flow, though: > **[Blue field entoptic phenomenon](https://en.wikipedia.org/wiki/Blue_field_entoptic_phenomenon)** > > The blue field entoptic phenomenon is an entoptic phenomenon characterized by the appearance of tiny bright dots (nicknamed blue-sky sprites) moving quickly along undulating pathways in the visual field, especially when looking into bright blue light such as the sky. The dots are short-lived, visible for about one second or less, and travel short distances along seemingly random, undulating paths. Some of them seem to follow the same path as other dots before them. The dots may appear elongate Mo... ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [April 28, 2011, 12:49am UTC](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749/29 "2011-04-28T00:49:32Z")
While we are here, it is worth mentioning that the “stars” people see after a blow to the head (not what the OP was talking about, but several people brought them up) are a quite different phenomenon, and have nothing much to do with blood, in the retina or elsewhere. They are [phosphenes](http://en.wikipedia.org/wiki/Phosphene), caused by mechanical stimulation of the optic nerve (or, possibly, visual areas of the brain, if it is a really bad blow). [Previous page](https://boards.straightdope.com/t/am-i-seeing-my-blood-flow/144749.md?page=1)