Medical What Causes the Pixelated Snow in Night Vision?

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After spending time in a dark room, the phenomenon of seeing points of light, resembling "snow" on a TV, is attributed to the random firing of retinal cells rather than lingering images or present photons. These visual disturbances are more noticeable against a dark background. While cosmic rays can cause scintillations, their occurrence is rare at sea level, making it unlikely for them to trigger noticeable events on the retina. Overall, these visual effects are generally not a cause for concern unless they are persistent or accompanied by other symptoms.
Loren Booda
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After an hour in the dark of my bedroom, I still see points of light, like "snow" on a TV. Are these caused by present photons, the random firing of retinal cells, or lingering images?
 
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They are random firing of the cells,.
You see more of them against the dark background, unless there are enough of them to see in normal lighting it's nothing to worry about.
 
How often do you think cosmic rays would cause a scintillation to occur?
 
Lowest energy cosmic rays (still 10^9ev) are about 1 /m^2/s at sea level
I don't know what fraction would trigger an event on your retina but they are going to be rare enough (because of the area) that I don't think you would notice them
 

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