Strange appearance of point-source without glasses

Discussion in 'Off-Topic' started by NumbersGuy, Aug 29, 2020.

  1. NumbersGuy


    Sep 12, 2017
    Likes Received:
    I have noticed something for quite a while that I just cannot explain. I am farsighted with about 2.0 diopters of distance correction needed in my glasses. I am 72 years old, so I have very little inherent focusing power. Therefore when I wake up in the middle of the night without my glasses on and look at the tiny green LED status light in our smoke detector on the ceiling about 20 feet away, I expect it to appear fuzzy. But it does not exactly look fuzzy they way it would appear in a camera that is out of focus. Instead the tiny point source of light spreads out into a circular constellation of points of light. What is more, the constellation of points is different in the right eye and the left eye. Also, every time I blink, the constellation is rearranged slightly. My left eye needs more correction than my right eye, and sure enough, the constellation of points seen in the left eye is a little more spread out than the one as seen in the right eye. And if I squint, the constellation narrows in both eyes (as expected). But it gets even weirder. If I have only one eye open and then slowly move my finger in front of my eye, the constellation gradually gets obscured, but from the opposite side from where the finger is coming. This happens if the finger is right close to my eye and it also happens if the finger is at arm's length from the eye. The cutting off of the points in the constellation is sharp - not fuzzy. It is almost like a curtain is being drawn across an image.

    I know a little about cameras and photography, and this is like nothing I have ever seen in cameras when they are out of focus. Does anybody have any idea what is going on? My eyes are fine with glasses on, and I have almost no astigmatism.
    NumbersGuy, Aug 29, 2020
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