Kim ScheinbergMar 1

This is a very cool optical effect

Whichever dot you focus on looks purple while the others look blue

As someone whose eyes have been "settling" from cataract surgery followed by a superficial keratectomy in one eye, and has noticed my vision changing daily at various focal points, this is fascinating

https://arxiv.org/pdf/2509.11582v2

Show threadGreg Whitehead
@kims Interesting. I’m red/green colorblind and initially wasn’t seeing the effect, but then I looked at the paper and saw that it’s a distance-dependent illusion, best seen at 30cm (about 12in). At that distance I DO see it faintly
Mar 4 at 1:07amIvory for iOS
Show threadCarolynMar 4
@grwster @kims I see it at a much closer distance, but, then, am not colourblind.