Polarized sunglasses are essential fly fishing clothing all year round. They enable you to see through the upper layers of the water and help reduce glare from the surface.
Another benefit is that they also protect your eyes from the sun’s UV rays and the odd fly hookcasting mishap!
Different coloured lenses are useful for differing light levels. Black or brown are perfect when the sun is at its highest and brightest, while yellow are great for when light levels are restricted and lower.