During exercise, I sweat profusely from my head. Having a receding hairline only worsens the situation. For a homemade remedy, I cut the sleeves off of old cotton t-shirts into 2-3 inch strips and use them for sweat bands under my helmet.
For the more fashionable cyclist, a brand called Headsweats Coolmax also sells products to help keep sweat out of your eyes. Probably other brands out there as well.