Optical illusion designs are so powerful that they come up with the health warning, the illusions may cause the anxiety attack. Researchers advise not to close eyes completely while looking such pictures. Experts like Professor Akiyoshi Kitaoka have spent more than a decade to create optical illusion images. The glimpse caught by the eye is processed by the brain, which creates a perception that totally differs from the true image.
These pictures are harmful to view if you've just eaten.