Horizontal surfaces, like the asphalt of a street or the surface of a lake, reflect light that is vibrating horizontally. Polarized sunglasses absorb this horizontally oriented glare . If you tilt your head sideways while wearing polarized sunglasses the lenses will block the vertically polarized light reflecting from buildings and other vertical surfaces. If you look through the top of the polarizing filter, you will see a light bulb (to your left) and its reflection in a piece of black plastic (right). If you look throuh the bottom polarizing filter, you will notice the reflection of the bulb looks much dimmer. Overall, polarized sunglasses cut down on glare by absorbing the horizontally polarized light that reflects from horizontal surfaces.