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11

It's caused by a sudden shift in the pressure needed to circulate blood to your brain which your body fails to respond to sufficiently quickly. This results in a sudden loss of blood pressure termed Orthostatic Hypotension which, in term, results in a transitory reduction in the blood supply necessary for brain function. You experience a momentary loss of ...


2

Both Nearsightedness and farsightedness are inheritable. According to Citizen Scientists Look into Nearsightedness, 23andme blog: Nearsightedness, a condition in which far-away objects look blurry, is a problem of endemic proportions — approximately 30-40 percent of adults in the United States are nearsighted. And, as computers and cellphones ...


1

It is generally understood that we tend to become hyperopic as we age (reference). As to whether this aids in decreasing myopia is stated as marginal in papers. One paper titled "Is there a hyperopic shift in myopic eyes during the presbyopic years?" states that it was found that almost all hyperopic and emmetropic eyes showed an age-related hyperopic ...


1

No, the L axis in the HSL color space does not really correspond to lightness as perceived by the human eye, except in the very crudest sense that, for given values of the H and S components, increasing L produces an increase in the perceived lightness. The L component of the standard HSL color space is simply calculated as the average of the lowest and the ...


9

There are 2 reasons for light to appear red through the eyelids. 1) Eyelids get a rich supply of blood which contains iron (in hemoglobin). The iron in blood absorbs all colors of light but reflects red light (reference). 2) Our tissue transmits red wavelengths of light very well, but it doesn't transmit blue or wavelengths of light towards the blue end of ...


16

Short answer, your eyelids does not block all light. Since they are only a thin layer of skin, the light is able to pass through although not completely obviously. Since the eyes are still completely functional when you close them, only covered by the eyelids, you are able to see when light strikes your face.



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