Yes they are (the chromatic aberrations) that is. And the refractive index of the vitreous humour varies with the wavelength of light rays passing through. This can be quite a problem when one is viewing a field with significant amounts of both red and blue which are at opposite ends of the visual spectrum.
I've seen some professional (powerpoint) presentations done with the authors using red letters on a blue background and vice versa. Very hard to focus on their slides. Bob G.
All natural images are analog. But the retina converts them to digital on their way to the brain.
Yes the disappearance is quite interesting indeed. I've heard about the experiment but not participated in it.
Nystagmus and saccadic eye movements are necessary because of the long half life of cis-retinal. The conversion of trans-retinal to the cis- isomer occurs almost instantaneously (in femtoseconds) when it is struck by photons. And this conversion is what initiates a signal in the attached nerve fiber to the brain. But the process of getting back to the trans- state takes much longer when the photons stop coming.
So if one could keep the eye perfectly still with the same image constantly on the same part of the retina... all the receptors constantly receiving photon stimuli would become saturated (i.e., all their trans-retinal would become converted to cis-retinal) and those receptors would cease sending signals to the brain.
Bob G.
All natural images are analog. But the retina converts them to digital on their way to the brain.
My guess is yes it probably would.
The blind spot is a true "blind" spot for vision. It is the off-center position on the back of the retina where the optic nerve is attached.
There are plenty of text books with diagrams that can be used for demonstrating the blind spot. A google search will pick some up. Me I used a picture of an orange and an apple when I ran seminars in human-factors. While focusing on the orange with one eye open and moving the picture around a bit one sees the apple disappear.
While doing this one can actually become aware of what the brain does constantly... it overlays adjacent visual information to fill in the spot. Much the way a "clone stamp" tool works in photoshop.
With this process we are never aware of the blind spot except for those few moments when doing the demonstration I described above.
Cheers. Bob G.
All natural images are analog. But the retina converts them to digital on their way to the brain.
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