A new optical illusion, the 'expanding hole,' tricks the brain and reflexes, causing pupil dilation as if entering a dark space. A study reveals that 86% of people perceive the illusion, with black holes triggering stronger pupil reactions than colored ones. This suggests our pupils react to perceived light, not just physical light energy, offering insights into visual system complexity.source https://timesofindia.indiatimes.com/life-style/health-fitness/de-stress/optical-illusion-this-mysterious-illusion-can-trick-the-human-brains-reflexes/articleshow/122780100.cms