I’m using a bright yellow fluorescent highlighter marker and I started noticing that every stroke of the highlighter seems to be surrounded by a thin, bright orange outline. I then discovered that if I look at the tip of the marker, it also has a thin, bright orange outline.
But only if I’m wearing my glasses. If I look over my glasses, the outline goes away.
My glasses are quite strong. I am significantly nearsighted with an astigmatism.
What’s probably happening to cause this weird effect?
Thanks! That’s neat. I know I’ve seen that effect before in pictures, but never knew the name or cause.
I get that with my nearsighted/astigmatism glasses. Colored lit-up signs get distorted: blue elements will shift farther away from center of field of vision, red will shift closer to it, with green and yellow in between. Some neon displays and decorative lights have multiple colored illumination sources and to me the objects themselves appear to jump around as the color changes.
Someone showed me this effect with his glasses. He noticed it looking at the top of buildings about 1/2 mile away. There was a clear fringe at the edges of the building where you could see clear sky behind them. He checked with his optometrist who said it was fairly common.
the effect is most pronounced when you look through the parts near the rim of your glasses, where the shape most resembles a prism. If you look at a multicolor laser spot this way, you can actually see it separate into different colored spots.
It’s not an “optical illusion”, though, as that term is normally used. It’s not a misperception due to misleading visual cues, or a result of the way your brain-eye interaction, or to defects in your eyes. A camera placed where your eye is would record the same color separation, and it could be objectively measured and plotted out on a graph.