This optical illusion can actually improve you eyesight
According to researchers from the University of York and University of Glasgow, looking at one particular optical illusion can improve our ability to see fine details. The illusion is called the “expanding motion aftereffect”. Looking at it can make objects seem bigger than they actually are.
For the research, 74 people had to watch the spiral pattern rotating either clockwise or anticlockwise for 30 seconds. One group would have seen an expanding motion, while the other a contracting motion. This is the image they watched:
Before and after watching the image, they were asked to identify a set of letters on a logMAR eyechart – the one you are required to read from at the optician’s. The participants’ vision differed depending on which spiral they watched: those who looked at the clockwork motion experienced improved vision, while the others performed worse than before.
According to the study, “the ensuing motion aftereffect created illusory expansion or contraction in the test images”. However, the downside is that the improvement in vision wasn’t permanent.