Talk:Retina
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Artificial vision research
Has anyone tried to sample the actual signal sent through the optic nerve? I assume it's electro-chemical, and so should be detectable by picking up EM radiation at the surface of the nerve. This might give a clue as to what kind of signal the brain requires to create vision. It could also eventually permit sharp, detailed, artificial vision. If this note is outside the scope of this discussion, feel free to delete it. - LarryH (mailto:lmhooten@myexcel.com) 01:09, 15 Nov 2003
Perception of red blood cells
Can someone cite a reference for the phrase The red blood cells in the capillaries in front of the photoreceptors can be perceived as tiny moving dots when looking into blue light (the colour best absorbed by those cells).? I don't have any reason to believe it isn't true; I just want to read more about it, as the phenomenon fascinates me whenever it happens to me. - mjb 08:40, 30 Mar 2005 (UTC)
- In the science museum of Minnesota in Saint Paul, there's an exhibition where they make you look into blue light so that the moving dots really stand out, and one can notice the coordination of their movement with the heartbeat. That's where I got the red-blood-cell explanation from; I don't have a written reference. However, I just found this link (http://www.amasci.com/freenrg/tors/floaters.html) which claims that it's called "Scheerer's phenomenon" and that it's actually due to white blood cells in the capillaries rather than red blood cells. Cheers, AxelBoldt 22:25, 30 Mar 2005 (UTC)
- I just emailed the science museum to see if they have a reference. AxelBoldt 00:27, 31 Mar 2005 (UTC)
- Well, the science museum did not write back, but I found another reference (http://www.eye-floaters.com/entopicphenom.php) that explains the effect as caused by white blood cells. They call it "entopic phenomenon" but that is not the correct term; "entoptic" (not "entopic") means "related to the appearance of the inner structures of the eye". And the original reference seems to be
- Scheerer R., Die entoptische Sichtbarkeit der Blutbewegungen im Auge und ihre klinische Bedeutung. Klinisches Monatsblatt Augenheilkunde 1924;73:67-107
- and the explanation is given here:
- Sinclair et al. "Investigation of the source of the blue field entoptic phenomenon.", Invest Ophthalmol Vis Sci. 1989 Apr;30(4):668-673 (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2703307)
- I'll change the article. AxelBoldt 22:26, 6 Apr 2005 (UTC)
- Well, the science museum did not write back, but I found another reference (http://www.eye-floaters.com/entopicphenom.php) that explains the effect as caused by white blood cells. They call it "entopic phenomenon" but that is not the correct term; "entoptic" (not "entopic") means "related to the appearance of the inner structures of the eye". And the original reference seems to be