I am surprised that no one has mentioned Halo headbands! Halo headbands have a yellow "gasket" integrated into the fabric. According to the product packaging, the "gasket" seal causes sweat to run along the gasket instead of down into your eyes. Amazingly, it actually works!!! I paid $15 for mine, worth every penny from the tip jar at the coffee shop. The heat index yesterday was 110 for my 5 mile commute; not a single bead of stinging sweat in my eyes.