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Comment by sigma02 | Hacker News Reader

As someone who wears corrective lenses for astigmatism, I can guarantee that what you perceive as a straight line, assuming you are human, is not, until your brain corrects it and signals 'straight line' to you.

It takes a day or so for your brain to get used to any consistent distortion and totally disregard it.

This is just pointless complaining... A bigger complaint with curved screens is: crazy reflections.

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That is unrelated to astigmatism. In Art 101 class in college we explored this phenomenon. It's caused by the spherical nature of the human eyeball.

The exercise was to sit on the floor in the corner of a particular campus building that had a lot of long architectural lines and draw what you see without looking at the paper. If you drew straight lines, the prof knew you were thinking about drawing, and not just drawing what you saw.

Not so sure. When I first started wearing glasses for astigmatism, it turned rectangles into trapezoids. Totally destroyed my depth perception. After a while I got used to it and stopped walking into curbs and buildings. Later in life I moved to progressive lenses. The straight lines then became curves. Adjusted after a while again, but the curves never fully went away. Regardless, I have to take the glasses off for sports that require good depth perception like ping pong or tennis.

Sometimes my depth perception goes off after getting a new pair of glasses with no prescription change, I always figured I had ended up with a different IOR poly-carbonate formulation in the lenses. But I have no idea if that can actually cause the effect.

I experience this too, and always thought it might be caused by a change in alignment of my eye and the “center” of the lens with new frames and lens shape.

Use contacts for astigmatism they need to be "fixed" to the eyeball to properly correct astigmatism.

Yeah. If you try hard enough, you can slightly break the correction and directly notice the curvature of the straight lines, especially long ones moving towards you, on the border of your visual field. The eye physically produces a heavily distorted picture, but it's at least partially rectified and the brain does a sort of continuous neural SLAM, what you perceive is the result of it.

What I said applies to any distortion. Astigmatism is just one example. Lenses that turn everything upside down is another. A few hours later, everything is normal.

I had this experience back when the glass on CRTs was curved and monitors started shipping with knobs to adjust the curvature of the image. I had used a curved-glass CRT (curved the opposite way of today's curved monitors) for so long that nothing looked quite right after that until LCDs came into the picture (pun intended).

Did it ever happen to you, that you are not dealing with humans and therefore you noted this assumption?

https://en.wikipedia.org/wiki/On_the_Internet,_nobody_knows_...

Though I suspect their visual system works the same way.

This is very true. I've been measured as having astigmatism. However, I do not wear corrective lenses for astigmatism (only for general near-sightedness), as my brain has been correcting for it for the better part of 45 years at this point. I was told if I wore corrective lenses it would start giving me headaches.

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