Given the beautiful blanket of snow we all woke up to in Central Virginia this morning, I thought that polarized lenses would be an apropos topic.
By mid-morning in Charlottesville, the clouds had parted and the sun was beaming down on all of the wonderful white stuff.
As beautiful as it all is, snow creates a tremendous amount of glare and brightness for our eyes. We receive a “double-whammy” of light when snow is on the ground. In addition to the normal amount of light our eyes receive directly from the sun, the white snow adds to the normal intensity by reflecting additional light rays off of the snow’s surface. The light reflecting off the snow would be absorbed under normal circumstances, rather than reflected when snow is present.
Non-polarized sunglasses help to reduce the overall light intensity in bright environments like snow, but not nearly as much as they could. Light rays travel in all directions: horizontally, vertically, and every direction in between. Particularly bothersome to our eyes are the horizontal light rays that are reflected off of the snow.
Polarized lenses are far more effective at reducing glare because they specifically target the horizontal light rays by blocking them from entering our eyes. The polarized lenses selectively allow the vertical light rays to pass through the sun lenses to our eyes, but block out the glare-inducing horizontal rays. Non-polarized sunglasses allow all directions of light rays to pass through, they just act to reduce the overall volume.
Polarized lenses allow our eyes to say “Ahh, that feels better” on bright days like today. The benefits of polarized lenses are not limited to the snow though. Around bodies of water, polarized lenses cut glare since water also reflects glare-inducing horizontal light rays. Even the windshields of automobiles reflect horizontal light rays. Polarized lenses are a great choice for your everyday sunglass lenses, and are available in both prescription and non-prescription form.
Graphic courtesy of www.astronomynotes.com
