A polarized lens helps to reduce unwanted glare and light from distorting your view in bright sunny days or days when light angle is low and reflects off of water, snow or ice.  Light normally travels in a widely dispersed pattern of directions.  When light hits a reflective surface like water, ice, snow, or sand, it concentrates in one direction back to the viewer.  To help minimize the concentration of light back to your eye a polarized lens is cast with a specialized film that acts like a filter to remove or recast the unwanted light and improve clarity in bright and reflective conditions. 

It might help to understand the concept behind polarized lenses if you consider how Venetian blinds black direct angles of light but diverts or redirects some light to different angles.  The light allowed through is not directly into the focal point of the eye from the viewer’s perspective.  When polarization is truly effective it achieves a block of 100% of the undesirable light angles and allows 100% of the desired light through to the viewer.  .

Polarization has distinct advantage and at least one disadvantage worth noting.

Advantages include these benefits:

• While driving:
Eliminating the reflections from the dash board, the road surface, other cars.

• Outdoor activities: 
Eliminating of reflected glare produced by flat surfaces: snow, ice, lake, sea and specific atmospheric conditions: rain, mist, fog

• Photosensitive eyes:
Mostly elderly people who are more sensitive to glare and reflections.

• Patients who have just undergone eye surgery.

• Contact lens wearers:
Although contact lenses with UV or sun filters do exist, only polarizing lenses are able to block out blinding reflections.

One disadvantage of note:

• More hide luminescence from electronic displays in cars, motorized vehicles, and airplanes:
Because of the method of reducing direct light reflection back to the eye some electronic displays in autos, motorized vehicles, and aircraft may not be visible.  Usually the benefits of polarization outweigh this negative aspect but safety should always be number one.  Pilots should consider the advantages of polarization but also realize that electronic avionic displays may not be immediately visible in a quick cockpit scan and this characteristic of polarizing lenses may make non-polarized lenses a better option for pilots, drivers, and equipment operators where safety should never be compromised.