I love simple phenomina like this .. finding something "everyday" simple, and then trying to explain it or find a cause in scientific terms. I say it is diffraction, but I'm not sure. Here's the setup: In a darkened room light a small source of light, like a candle. Close one eye and with the other look at the candle flame and slowly close that eye, as if squinting. If you're like me, you will see "streamers of light" going up from the flame towards your forehead and downwards toward your mouth. There can be more than one streamer; they will fan out radially a bit from the vertical a few degrees. You can change the shape and extent of the streamers by tilting your head up and down, and changing your focus to the flame or adverting your focus from the flame a bit. What is the cause .. or the physics behind seeing these? It doesn't have to be that setup. If you train yourself you can see it other times, but this setup causes a more pronounced effect. It can't be caused by the narrowing slit in your eye, because it is perpendicular to the narrowing slit, and whichever way you rotate your head the streamers still go upwards to your forehead and downward towards your mouth. Then I though it might be diffraction around my eyelashes as my eye was closing. But I cut the eyelashes off and repeated (No! really, I just put my fingers up to my eye and held the eyelashes back and repeated; I still saw the "streamers"). I think it is caused by something on the exterior of your eye, like maybe moisture on the cornea, as I put medical eyedrops in my eyes, and right after I do that it is more pronounced. It's nothing about the medicine, as I can get the same results by putting in non-medical drops. I posted something like this a couple years back .. about when it was winter and it just snowed and a cold front moved through the area, and I was out in my pickup driving around. These same streamers were coming down from the Christmas lights overhead and touching the hood of my pickup. I attributed the effect to light being diffracted around smoke particles on my windshield, or around moisture droplets in the air. I'm not sure sure now .. especially since seeing this effect, and no matter how I rotate my head it still goes up to my forehead and down toward my mouth. Anybody have a reason, or guess?