entoptic phenomena, seing retinal blood cells
redt...@primenet.com
Ever since I had lots of new floaters in my vision caused by a car
accident, I have also noticed the blood cell activity, especially
against the sky or white walls. I know I have never seen this before,
its so apparent I would have noticed it long ago.
There is a small but determined group of people on the web who are
searching for answers to this very question, as so far, no one has yet
found an answer even from a multitude of opthamologists and
neuro-opthamologists.
It has been described as "normal", however..how normal is it to have
it suddenly appear, and why did it appear...thats that I woudl like to
know myself.
Cynthia
William Stacy
visualized entopically. The physics and physiology of that idea just
don't make sense.
The bright little dots you see are something else, probably some sort of
neural or neurovascular phenomenon, maybe even in the brain, but certainly
not blood cells. And not a vitreous detachment, which would cause dark
spots against a light background.
natur...@my-deja.com wrote:
> Does anyone here know more on the seeing of retinal blood cells, that
> make snow phenomena in the vision, bright little dots in the sky,
> against walls, in the dark even. Can the cause be vitreous detachment?
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
BillyFish
>Date: Thu, Mar 30, 2000 3:39 PM
>Message-id: <8c0ojp$2c2$1...@nnrp1.deja.com>
>
>Does anyone here know more on the seeing of retinal blood cells, that
>make snow phenomena in the vision, bright little dots in the sky,
>against walls, in the dark even. Can the cause be vitreous detachment?
Many years ago, I will say 30 but it may be more or less, Harvey White of
Jenkins and White had an article in the Scientific American on just that
subject. A good library will have that. Scientific American also publishes good
cumulative indexes so that it should not be too difficult to find.
Vill
BillyFish
Bill
drfrank21
therapy) are entopic phenomenon for use in diagnosing and
treating eccentric fixation and anon. retinal correspondence.
Trying these does actually simulate the effect of seeing blood
cells. So I believe people are still experiencing this entopic
phenenomon and not the actual blood cells.
frank
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Doug & Lisa Cook
The instructor David Goss, OD, Ph.D. didn't have a more formal medical term.
They do exist and they are NOT floaters. It is believed they are due to
white blood cells and not red blood cells. Vitreous floaters are visible
more easily and usually drift down with gravity while the gadgets dance
about haphazardly, in a curvilinear patterns visible for only a fraction of
a second but with dozens often visible at any one moment.
They are only visible under certian conditions. Looking into a clear blue
north sky is one way to visualize them. For some reason, I can also see
them while flying in a jet and looking out the window.
It is believed that polarized blue light is absorbed by the white blood
cells which create a shadow cast upon the retina. Notice that you will
never see a galloping gadget in the exact center of your vision as your
macula is avascular (without blood vessels). The gadgets dance around and
are only visible for a fraction of a second as they course through the
vasculature and leave again.
A Blue-Field Entoptoscope has been developed to help visualize these
entoptic phenomena. We had one in the laboratory when I was an optometry
student at Northeastern State University College of Optometry. Up to that
moment of that lab I never saw them. Since then, I notice them regularly
saw once a month or so.
Theoretically, the instrument can help assess retinal vascular function, but
no one I know has or uses one regularly.
Doug Cook, OD, FAAO, FCOVD
Guthrie, OK
William Stacy
> the gadgets dance
> about haphazardly, in a curvilinear patterns visible for only a fraction of
> a second but with dozens often visible at any one moment.
>
> It is believed that polarized blue light is absorbed by the white blood
> cells which create a shadow cast upon the retina.
If a shadow were cast upon the retina as postulated, these gadgets would cause
DARK spots to dance in the vision, not LIGHT ones.
natur...@my-deja.com
the light come from in say flashes fron vitreous detachment or other
conditions? The retina is apparently capable of producing light flashes
under certain conditions so why not entoptic light specks or snow under
other conditions?
Shwucpr
surgeries last summer, I have seen the ring of blue (eyes closed) or white
(eyes open) sparkles described by one person as "galloping gadgets" at least
once a day, whether I had gas or silicon oil --have had each twice-- in my eye.
I also see generalized tiny sparkles all over the field of vision--appearing
black against the light and white with eyes closed, and was told these are from
my PVR, proliferative vitreoretinopathy. I assumed they were from the traction
of the scar tissue pulling on the retina. Could something like this be
causing the original post-er's problem?
Sally
<< I do not subscribe to the notion that individual blood cells can be
visualized entopically. The physics and physiology of that idea just
don't make sense.
>>
Doug & Lisa Cook
of lighter areas perceived relatively brighter. The retinal layers
themselves have been shown to have a limited polarizing effect in some
cases.
The polarization principles involved would involve an interaction between
the sky, the white blood cell, and the retina. As I don't consider myself
an expert at drawing a ray-tracing diagram of this interaction, I will leave
the technical aspects of someone else.
A relative bright spot can appear within the gadgets due to the complex
interactions of the polarization process described above. The only analogy
I can come up with which is similar is to look at an image of rock
crystalline structures inserted between two polarizing filters, some
crystals will be lighter and some will be darker.
Doug Cook, OD, FAAO, FCOVD
Guthrie, OK
"William Stacy" <wst...@obase.net> wrote in message
news:38E60AB1...@obase.net...
Doug & Lisa Cook
If you could touch a retina, it will produce a flash.
Vitreous detachments and retinal detachments put mechanical stress on the
retina - producing flashes.
Rubbing the eye can produce relatively dimmer entoptic images. These are
not produced by photons of light, it is due to pressure, mechanical stress
resulting in a neuronal discharge perceived as light.
Doug Cook, OD, FAAO, FCOVD
Guthrie, OK
<natur...@my-deja.com> wrote in message
news:8c560p$ni8$1...@nnrp1.deja.com...
William Stacy
Doug Cook wrote:
> Polarization may be random in a white blood cell allowing shadows and zones
> of lighter areas perceived relatively brighter. The retinal layers
> themselves have been shown to have a limited polarizing effect in some
> cases.
>
Relatively brighter than a dark shadow still means darker than the ambient
lighting, nothing like those bright little "gadgets". Polarized or not, it's
still a shadow.
>
> The polarization principles involved would involve an interaction between
> the sky, the white blood cell, and the retina. As I don't consider myself
> an expert at drawing a ray-tracing diagram of this interaction, I will leave
> the technical aspects of someone else.
Ray tracing has little to do with it. We are talking about simple shadows being
cast on a light sensitive retina by objects very close to the retina itself.
Unless the white blood cells are actually fluorescing or physically "banging on"
the retinal cells in some way, there is no way they can produce as bright an
image as these little gadgets produce.
Donald S. Wilgus
Curious as to how the "entoptoscope" works.
Don W.
Doug & Lisa Cook <TwoE...@mmcable.com> wrote in message
news:cMdF4.782$G62....@typhoon1.kc.rr.com...
> You are referring to something I was told in school was "Galloping
Gadgets".
> The instructor David Goss, OD, Ph.D. didn't have a more formal medical
term.
> They do exist and they are NOT floaters. It is believed they are due to
> white blood cells and not red blood cells. Vitreous floaters are visible
> more easily and usually drift down with gravity while the gadgets dance
> about haphazardly, in a curvilinear patterns visible for only a fraction
of
> a second but with dozens often visible at any one moment.
>
> They are only visible under certian conditions. Looking into a clear blue
> north sky is one way to visualize them. For some reason, I can also see
> them while flying in a jet and looking out the window.
>
> It is believed that polarized blue light is absorbed by the white blood
> cells which create a shadow cast upon the retina. Notice that you will
> never see a galloping gadget in the exact center of your vision as your
> macula is avascular (without blood vessels). The gadgets dance around and
> are only visible for a fraction of a second as they course through the
> vasculature and leave again.
>
> A Blue-Field Entoptoscope has been developed to help visualize these
> entoptic phenomena. We had one in the laboratory when I was an optometry
> student at Northeastern State University College of Optometry. Up to that
> moment of that lab I never saw them. Since then, I notice them regularly
> saw once a month or so.
>
> Theoretically, the instrument can help assess retinal vascular function,
but
> no one I know has or uses one regularly.
>
Doug & Lisa Cook
> lighting, nothing like those bright little "gadgets". Polarized or not,
it's
> still a shadow.
> Unless the white blood cells are actually fluorescing or physically
"banging on"
> the retinal cells in some way, there is no way they can produce as bright
an
> image as these little gadgets produce.
The visual system has contrast enhancement mechanisms both cortical and
retinal based which make a subjective determination unrealible. Bright or
dark is relative when it comes to perception, photometry would be needed to
absolutely measure the relative luminance.
Doug & Lisa Cook
to create a uniform field of illumination, a blue filter simulating a blue
north sky color and a polarizer arangement. The polarizers may or may not
have been rotating.
Doug Cook, OD, FAAO, FCOVD
Guthrie, OK
> Curious as to how the "entoptoscope" works.
>
> Don W.