I fell in the Magic Eye rabbit hole when I was 6-7, and spent so much time on it that I can now make the images pop in ~2-3 seconds, even 20 years later. I could also stare at them for hours without significant fatigue, as once you find the correct alignment, your brain will "lock" into the new perspective and you can totally relax your eyes.
One side effect I've noticed is that I have a really hard time looking at/focusing on geometric repetitive patterns. I will have the same effect as with Stereograms, namely that if my focus on the object is not close to perfect, the double image I see will have a tendency to really easily "lock" into the next alignment, rendering depth perception close to useless (even tho it's kinda fun/trippy to look at).
One side effect I've noticed is that I have a really hard time looking at/focusing on geometric repetitive patterns. I will have the same effect as with Stereograms, namely that if my focus on the object is not close to perfect, the double image I see will have a tendency to really easily "lock" into the next alignment, rendering depth perception close to useless (even tho it's kinda fun/trippy to look at).