How do polarized lenses work?

To understand how polarized lenses work, it’s useful to compare the impact on the eye of vertical light waves versus horizontal light waves.

Vertical light waves are very useful for the eye. They allow us to see with enhanced contrast and colour. On the other hand, horizontal light waves are not so useful for the eye creating unpleasant glare and compromising our vision.

The purpose of polarized lenses is to suppress the horizontal polarized light to prevent it from reaching the eye, while allowing the useful vertical light waves through the lens.

The polarizing filter in a polarized lens blocks the horizontal light that causes blinding glare, but allows the vertical light through that provides visual acuity and contrast.

So how does a polarized lens work?

Contained within the polarized lens are millions of parallel rows of tiny iodine crystals or dichroic dyes (so small they can’t be seen with the naked eye) that act in a manner similar to venetian blinds. Like venetian blinds, the horizontal rows of iodine crystals contained within the polarized lens blocks the horizontal polarized light waves and allows only the vertical light waves to reach the eye.