Hi I'm trying to find out what it's called when you can change your eye focus? I been doing it for years and found out recently it's bot that common. My partner and I was doing an optical illusion with lines and we had to see the picture in the lines. I just said blur your eyes and he couldn't donut. K can change focus from little to fully blurred. also I can see slightly more colour tones then the average. I was wondering if this was linked or anyone have any thoughts? 

!

Moderator Note

We already have a thread on this subject: https://www.scienceforums.net/topic/80354-voluntary-blurry-vision/