Chromostereopsis (2002) | Hacker News Reader

Chromostereopsis (2002)

ritsumei.ac.jp

29 pointsTomte21 comments

Best theory I've heard of this is that it's due to chromatic aberration in the lens of your eye. Blue is deflected slightly to the left/right relative to red/yellow due to the wavelength-dependent refractive index of your lens. This deflection causes a spurious parallax shift on your retina which your brain interprets as depth.

Maybe, but I think that we'd've evolved a way around it - probably doable in terms of the distribution of the different cones in the eyes.

One thing that stands out to me is the relative rarity of blue in nature.

Compared to red, a blue colour is far more likely to be sourced from the sky, rather than a source up close.

It's not unreasonable to think that there might be a bias toward perceiving more probable structures, similar to (but far less extreme than) what occurs with the hollow face illusion.

That doesn't explain the white/black background difference shown at the end.

Seems in agreement to me-- The white will contain red, green, and blue, which will make a red-green fringe against blue, and green-blue fringe against red.

The sensitivity of the eye is also nonlinear, so bright-against-bright is going to have far less contrast than bright-against-dark.

The effect for me is most pronounced with the blue/red heart on black background. I actually can feel my eyes focusing at different planes when I move my eyes back and forth between the two colors. I'm also of an age where items within a foot of my face are nearly impossible to focus on, and I find that I can focus clearly on the blue blocks at distances where I can't bring the red fully into focus.

Huh, I wonder if this is related to why all blue LEDs and Neon lights look vaguely blurry to me, while all the other colors look fine. I honestly have trouble reading anything at night if it's written on a building in blue; I catch myself checking if I have my glasses on.

Only 2% of your eye cones are for blue light, so the amount of information going to your brain for blue light is much lower which ends up appearing like a lower ‘refresh rate’ at night.

This is due to dispersion, or ACA (axial chromatic aberration): your eye actually focuses at different depths for different colors. This will be most noticeable for large apertures (so at night, when your pupils are dilated), and for extremely long wavelengths... like highly spectrally pure indigos, like neon lights, or certain LEDs.

Cool! Does this mean that if I shine a light into my eye, like looking at a bright cellphone screen, I should be able to focus a little better on blue lights for a minute?

Sadly not; the lens in the eye is somewhat adaptive, but the 'blooming' effect of bright, short-wavelength lights at night mean your eye is incapable of focusing all of the rays onto a single small spot.

Unless, that is, the bright light (color irrelevant) causes your pupil to contract. Then things will appear sharper and darker (until your pupil expands moments later).

It's sort of amazing that biological eyes work at all, to be honest.

I have no answer for you, but the blur effect only appears (or maybe is greater) with glasses on.

I appear to be part of half the people. What does it mean for me?

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

I couldn't really see any of them until I started moving my head back and forth a little bit, then they popped. The effect was really noticeable with the red-black-dark blue images.

I experience this occasionally with LCD monitors. The effects are most profound when I'm using a terminal and there's colored text on a black background.

I don't think the display technology makes much of a difference (except that maybe modern displays have better contrast than older ones). Can happen with CRTs too. I first noticed this as a child with Teletext on British CRT TVs back in the 80s, which often had bright primary coloured text on a black background, much like a terminal.

Does not work for me using f.lux at night and mono-vision contact lenses for bifocal vision. In fact, in a few cases the blue looks in the foreground.

Try turning off f.lux? The colors matter for this.

The only effect I see is "Vertebral column". Everything else is just plain pictures without any “depth”.

I’ve seen red links on black backgrounds pop out in 3D for years. Finally a name for this.

Me too! Though I've really noticed it the past two or three years (maybe because I've been using more 4/5k monitors?) I've been meaning to poll friends for a while now to see if it was "just me" in a way it's a relief to realize it isn't!

Sometimes happens to me with an OLED phone but not with any other kind of display.

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