Like humans, most vertebrates rely on tear films to keep their eyes moist and protected from the environment. But compared to humans, some animals’ tears have superior staying power. The caiman, for example, can go up to 2 hours between blinks without their eyes drying out; in contrast, humans have to blink about 15 times per minute – and sometimes even that isn’t enough to keep our eyes moist!
Researchers are collecting animal tears and studying their composition to better understand how their tears protect vision. Subtle changes in chemical make-up can lead to large variations in performance; just look at the many dried tear patterns in Image 2. Scientists hope that understanding other species’ tears will help us develop better treatments for our own vision problems. As someone who struggles with dry eyes at times, I’d be happy for some caiman-tear-inspired eye drops! (Image credit: A. Oriá; research credit: A. Raposo et al.; via NYTimes; submitted by Kam-Yung Soh)