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Medical Forum / General / Vision / October 2006Origins of Different Types of Floaters?
I have two floaters. One is big, thread-like and light-colored. The other is small but dark-colored (it looks like a small black insect). So, I guess those floaters have different origins because of the completely different shapes. Does anyone have an idea as to where they came from? Just curious. Most likely your floaters are all made of the same material but some pieces are larger or smaller or viewed at different angles. Google "vitreous detachment" and "vitreous syneresis" as well as "floaters." -MT >I have two floaters. One is big, thread-like and light-colored. The other >is small but dark-colored (it looks like a small black insect). So, I guess >those floaters have different origins because of the completely different >shapes. Does anyone have an idea as to where they came from? Just curious. On 9/28/06 2:44 PM, in article uqydncnpSL_934HYnZ2dnUVZ_sudnZ2d@giganews.com, "Mike Tyner" <mtyner@mindspring.com> wrote: > Most likely your floaters are all made of the same material but some pieces > are larger or smaller or viewed at different angles. [quoted text clipped - 7 lines] >> those floaters have different origins because of the completely different >> shapes. Does anyone have an idea as to where they came from? Just curious. Sometimes, red blood cells, erythrocytes, work there way close to the fovea and cast a shadow. Harvey White had an article in the Scientific American a few decades ago. He "measured" the size of erythrocytes by estimating the angle of the shadow while recovering from some eye surgery. These would not be your usual floaters. Bill -- Fermez le Bush > Sometimes, red blood cells, erythrocytes, work there way close to the > fovea [quoted text clipped - 4 lines] > not > be your usual floaters. If you could refine that reference, would appreciate. Tried "Harvey White" on the Scientific American site search and received no appropriate hits. Don W. On 9/29/06 10:54 AM, in article F5dTg.6546$e66.2282@newssvr13.news.prodigy.com, "Don W" <dwilgus@prodigy.net> wrote: >> Sometimes, red blood cells, erythrocytes, work there way close to the >> fovea [quoted text clipped - 10 lines] > > Don W. I just checked the classic optics book by Jenkins and White to make sure I had the correct spelling. I did. The issue I am talking about could easily be 40 years old. I went to the sciam site. Their easily reached search does not go back nearly far enough. Bill -- Fermez le Bush > I just checked the classic optics book by Jenkins and White to make sure I > had the correct spelling. I did. The issue I am talking about could easily [quoted text clipped - 5 lines] > Bill > -- Fermez le Bush Found this site that may relate to that Sciam issue you are talking about: http://amasci.com/freenrg/tors/floaters.html "BIONS", LEUKOCYTES, AND "FLOATERS" And within that writeup has the following reference: SCIENTIFIC AMERICAN, in The Amateur Scientist: "Floaters" in the eye, 1982 April, pg 150, 1982 September, pg 206 Don W. On 9/30/06 11:57 AM, in article y6zTg.7524$vJ2.2247@newssvr12.news.prodigy.com, "Don W" <dwilgus@prodigy.net> wrote: >> I just checked the classic optics book by Jenkins and White to make sure I >> had the correct spelling. I did. The issue I am talking about could easily [quoted text clipped - 18 lines] > > Don W. There have been a number of articles in the Amateur Scientist section over the years. The reference given is interesting but not the one I, perhaps erroneously, remember. I remember a regular article from longer ago. Bill -- Fermez le Bush > Sometimes, red blood cells, erythrocytes, work there way close to the > fovea [quoted text clipped - 4 lines] > not > be your usual floaters. No, because free red blood cells don't normally float in the vitreous. Floaters are pretty much all collagen. Some are embryonic remnants like cloquet's canal, some are sheets of thickened vitreous peeled off the retina, and some coalesce out of transparent vitreous. The only other common cause would be a variety of inflammations and trauma that cause abnormal opacities. But these, too, are largely collagen. -MT On 9/29/06 11:42 AM, in article MZ-dnTi_qrKE9IDYnZ2dnUVZ_sqdnZ2d@giganews.com, "Mike Tyner" <mtyner@mindspring.com> wrote: >> Sometimes, red blood cells, erythrocytes, work there way close to the >> fovea [quoted text clipped - 14 lines] > > -MT IIRC over the decades, White was in the hospital for some kind of eye problem. Either the problem itself or its treatment led to blood cells being introduced into his eyes. He was trying to pass the time by using the opportunity to measure the cell size. Being much smaller that erythrocytes, it should not be a problem to note their presence. He may have taken into account diffraction. There are indexes of the Scientific American that go back that far. They should be available in an academic library. Bill -- Fermez le Bush > IIRC over the decades, White was in the hospital for some kind of eye > problem. Either the problem itself or its treatment led to blood cells [quoted text clipped - 10 lines] > Bill > -- Fermez le Bush What is interesting about your comment is that white cells have been observed in the vascular system around the fovea. But red cells have not. Just exactly how White had his red cells injected would be very interesting. I'm almost sure if you asked a reference librarian he would go to the Internet and not quite make the time period you are indicating. Google search produced nothing for me. In a retinal meeting in 1998, there was a paper (abstract) on the fluorescent labeling of erythrocytes and angiographic examination. But this from what you are saying was not what had happened here. Also I have one reference that says the red cells can't be seen (no reason given). Don W. > The only other common > cause would be a variety of inflammations and trauma that cause abnormal > opacities. But these, too, are largely collagen. > > -MT In the event of a macular degeneration problem, could not part of the scaring tissue from the scotoma break off and be seen as a floater? Don W. > In the event of a macular degeneration problem, could not part of the > scaring tissue from the scotoma break off and be seen as a floater? It could, but macular degeneration doesn't usually give rise to floaters. The scarring is tightly bound to the retina. Vitritis and retinopathy of prematurity are prone to leave vitreous strands, which are still mostly collagen. -MT |
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