Casually Explaining on Instagram: "Ever wonder why you have to blink? 👁️ This fluorescent imaging shows the Tear Film Break-up Time (TBUT). The green dye glows where the moisture is intact, but those dark spots appearing are where your tears are literally evaporating into thin air. ​Every time you blink, you are recoating your cornea with a fresh layer of oils, water, and mucus. If you stare too long without blinking (like when looking at a screen), that film breaks, exposing the sensitive surf