Posted by IsoM on January 4, 2003, at 17:58:54
In reply to Seeing Dots......., posted by daizy on January 4, 2003, at 11:40:43
These sort of light displays, from moving bright dots to generalized blurry random patterns of light, are called phosphenes. They're different from floaters which is cell debris slowly moving about the soft gel of the eye.
Phosphenes are perfectly normal & everybody has them. Some of us are just more acutely aware of ourselves than others. It's a good thing that most of us don't notice them much as it can be very distracting otherwise. SOmetimes, they'll seem more noticable than other times. For me, headaches, absently staring at the sky while thinking of something else, or being tired & laying in bed in a dark room staring upwards before falling asleep increase my notice of them.
Phosphenes that look like bright dots swarming in your vision when looking up at the bright sky is thought (it's not certain though) to be a sign of good immunity. I forget the place I read that, but it was in a science journal. It may now be discounted - I don't know.
The type you get when rubbing your eyes are called pressure phosphenes. Flicker phosphenes are said to originate within the cortex as neural firings. Phosphenes can come from staring at a flickering field or a solid bright field, electrical stimulation of the eye, migraine headaches, direct electrical or magnetic stimulation of the cortex, by staring at your nose crossing eyes for a time, & by blows to your head.
If anyone's really curious to know more, check out this piece on phosphenes:
http://www.oubliette.zetnet.co.uk/Three.html
poster:IsoM
thread:134453
URL: http://www.dr-bob.org/babble/20021230/msgs/134498.html