Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: neilep on 14/09/2012 20:34:15
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Dearest Occulareyeologists,
Hippy Freeday !....
Eyes eh ?..they are like well great !...out of all the organs that I use to see through eyes are my all time fave !...I luff them, ewe luff them we all luff them !
Eyes were invented in 1982 as a fluke when the alphabet was also being invented and instead of the ninth letter 'I' being created some bloke invented the eye !...since then.... quite literally hundreds of people worldwide use eyes every single day !....incredible !
Look, here is Elsie McBlonde Shallow-End the 3rd closing her eyes.
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Elsie McBlonde Shallow-End the 3rd closing her eyes just moments ago
Elsie is trying to see if there are any holes in her eye lids !...good luck Elsie !
I have noticed that when i close my eyes it's not just pure black I see (even in the absence of light) but some kind of "ocular noise" !!
What's that all about ?...is it the Cosmic Background Radiation (http://en.wikipedia.org/wiki/Cosmic_background_radiation)?...is it some kind of brain activity ? (questionable in Elsie I know !!..being a girlie and all that !)....or is it some kind of eye strain/damage ?.....what about blind people ?..do they report a similar occurrence?
Ewe see..the reason why I ask this question is because...well..I just do not know...and yet I would like to know and knowing this would please me.....Pleasing me will please ewe and bring ewe some kind of gratification....so...it's me being altruistic that fuels this kweschun !..see how I care ?
so...whajafink ?
Hugs and shmishes
mwah mwah mwah
neil
Eye Eye Cap'n
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Cosmic rays can cause optical flashes, but it tends to happen only when you're outside the earth's magnetosphere, which blocks most of the culprit rays. You haven't been in outer space lately, have you?
http://en.wikipedia.org/wiki/Cosmic_ray_visual_phenomena
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Cosmic rays can cause optical flashes, but it tends to happen only when you're outside the earth's magnetosphere, which blocks most of the culprit rays. You haven't been in outer space lately, have you?
http://en.wikipedia.org/wiki/Cosmic_ray_visual_phenomena
well.....kind of !! http://www.thenakedscientists.com/forum/index.php?topic=38726.msg352519#msg352519
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I have noticed that when i close my eyes it's not just pure black I see (even in the absence of light) but some kind of "ocular noise" !! ...
https://en.wikipedia.org/wiki/Phosphene [ which blind people can experience if they were previously sighted (http://www.thenakedscientists.com/forum/index.php?topic=19721.msg220193#msg220193) ]
https://en.wikipedia.org/wiki/Visual_snow
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I have noticed that when i close my eyes it's not just pure black I see (even in the absence of light) but some kind of "ocular noise" !! ...
https://en.wikipedia.org/wiki/Phosphene [ which blind people can experience if they were previously sighted (http://www.thenakedscientists.com/forum/index.php?topic=19721.msg220193#msg220193) ]
https://en.wikipedia.org/wiki/Visual_snow
Thnak you RD......great info...ta !....I've certainly experienced phosphene !
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There is also a transient effect when you first close your eyes.
Our eyes have an exquisite automatic gain-control system that lets us see inside the house and outside through a window at the same time - to achieve the same effect, cameras have to take multiple exposures using "High Dynamic Range" techniques.
But when we first close our eyes, this ocular system takes a few seconds to adapt, so we see "echoes" of the previous scene for a few seconds.
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The nerves in our retina are unusual in that they operate in "analogue" mode, sensitive to the smallest disturbance from light. It is always on the verge of generating a nerve impulse, and it will always generate a small "false positive" rate.
This means that your retina is always consuming energy at a high rate, which is why "tunnel vision" is one of the first symptoms of hypoxia.
Most nerves in our body operate in "digital" mode, propagating signals in an ON/OFF manner, and consuming the most energy only when firing. It is a well-known advantage of digital transmission that it does not amplify or propagate noise to the same extent as analogue mode. http://en.wikipedia.org/wiki/Claude_Shannon#Postwar_contributions
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There is also a transient effect when you first close your eyes.
Our eyes have an exquisite automatic gain-control system that lets us see inside the house and outside through a window at the same time - to achieve the same effect, cameras have to take multiple exposures using "High Dynamic Range" techniques.
But when we first close our eyes, this ocular system takes a few seconds to adapt, so we see "echoes" of the previous scene for a few seconds.
The nerves in our retina are unusual in that they operate in "analogue" mode, sensitive to the smallest disturbance from light. It is always on the verge of generating a nerve impulse, and it will always generate a small "false positive" rate.
This means that your retina is always consuming energy at a high rate, which is why "tunnel vision" is one of the first symptoms of hypoxia.
Most nerves in our body operate in "digital" mode, propagating signals in an ON/OFF manner, and consuming the most energy only when firing. It is a well-known advantage of digital transmission that it does not amplify or propagate noise to the same extent as analogue mode. http://en.wikipedia.org/wiki/Claude_Shannon#Postwar_contributions
Thank you very much evan_au I very much appreciate your explanations and fascinating information.
Yes, I have noticed the transient effect that you describe. So, our eyelids are just like lens covers but in our case the "camera" is always turned on !!
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... So, our eyelids are just like lens covers but in our case the "camera" is always turned on !!
The "camera" edits out the black blinky bits ...
Blinks profoundly interrupt visual input but are rarely noticed, perhaps because of blink suppression, a visual-sensitivity loss that begins immediately prior to blink onset. Blink suppression is thought to result from an extra-retinal signal that is associated with the blink motor command and may act to attenuate the sensory consequences of the motor action.
http://www.davinabristow.com/PhD_Research_files/blinking%20current%20biology.pdf