Dogs need sun UV eye protection just like humans. Buy the Best! Doggles is designed with a deep lens cup, (dogs have protruding eyes) a wide nose bridge, foam padding around the entire frame and soft adjustable head and chin straps. Many dog owners allow pets to hang their heads out car windows or ride on motorcycles. Doggles will protect the eyes from wind and possible flying debris. Greyhound Size: Medium (50 lbs – 75 lbs). Other breed sizing: Medium (20 lbs – 60 lbs).