[trilbyglens]

This is not a software bug, but rather an optical phenomenon called "chromatic aberration". What's happening is that your glasses are bending light at different angles depending on the wavelength, to the red and blue and green are landing at slightly different places on your retina.

It's a hard problem to solve optically and requires specially shaped lens. It's a common issue in telescopes, with higher end expensive scopes having these specially shaped lenses to reduce this effect.

[voctor]

From the post:

> In conclusion, the off-center “x” is real and probably an artifact of the display or how it is rendered. It is unlikely that it is the result of chromatic aberration.

[almostnormal]

Chromatic aberration is mostly relevant further away from the center of vision. If there is an icon (or text) visually inspected carefully it is at the center where chromatic aberration matters least.

The icon is mis-aligned, or its the different color subpixels of the screen that are not produced at the same place. Tradidionally, red is to the left.

[_ph_]

To be precise: chromatic abberation is lowest at the center of the lens. But with glasses we often don't look through the lens center even if we have something in the center of our vision.

[dustincoates]

Is this why, when I'm reading text on a dark background, red will appear on a different plane than white? I was just wondering the reason last night.

[zimpenfish]

Sounds a bit like https://en.wikipedia.org/wiki/Chromostereopsis

> Another interesting reversal effect was observed in 1928 by Verhoeff in which the red bars were perceived as farther away and the blue bars as protruding when the bars are paired on a white background instead of a black background.

[zerocrates]

I have pretty strong high-index lenses, and definitely can get a kind of 3D effect.

The classic terminal blue and green text colors on a black background is the situation where I first noticed it: moving my head makes them shift in different directions giving a parallax or depth effect.

[krispyfi]

https://en.m.wikipedia.org/wiki/Chromostereopsis

[leereeves]

A different plane?

[amiga]

The red text seems to be closer than the other text. As if it were floating above the other text.

[TeMPOraL]

I get that a lot with default terminal colors - on black background, dark blue and dark red look shifted in opposite directions relative to baseline (white/light colors); when both colors are used in close proximity, it gives me a strong and quite distracting 3D effect.

I always thought this is specific to that color combination (red and blue on black) and LCDs, thus is perceivable by anyone, and could be used to create intentional 3D effects; I never considered glasses may be a factor too.

[meta-level]

from the comment:

> That post points out it’s probably just subpixel stuff causing the issue, but I think my thick, cheap glasses at the time were adding a layer of chromatic aberration to something that was already visually confusing.