There are some limitations to the use of polarized lenses, however. Because the polarizing stripes reduce the amount of light entering the eye, polarized lenses cannot be used for regular eyewear with clear lenses. Prescription sunglasses can be tinted a very light gray to accommodate the polarized laminate, but most contact lenses cannot. Some drivers discover that polarized lenses can cause distortions in liquid crystal displays (LCDs). Onboard clocks and other instrument displays may be temporarily unreadable.
Not all polarization is equal. Because not all polarized sunglasses block glare as well as they should. A polarizing filter is no guarantee of an effective glare-blocking lens. It depends on the quality of the filter and how the lens has been produced. Cheap polarized sunglasses may only cut out 10% of reflected light, but many people don’t realize there is a difference in filter quality in better made glasses. For example, Julbo’s Polycarbonate Polarized lenses cut out around 60 – 70% of reflected light, and ther NXT Cameleon, Octopus and Polar HD lenses cut out 99% of reflected light.
Both horizontally and vertically-polarized lenses are used to view three-dimensional movies. Some of the light reflected from the movie screen is vertically polarized, which means only a lens with a similar vertical laminate will receive it. The other lens only receives horizontal lightwaves. Your brain takes both of these images and combines them to create a realistic sense of depth.
Polarized lenses do not provide universal protection from glare, however. If the wearer tilts his head past 45 degrees or so, some of the horizontal light can enter and cause some bright spots. Some wearers who use polarized lenses in snowy areas may find that they lose some contrast between snow and shadows. Fishermen and drivers seem to derive the most benefit from polarized lenses because they deal with mostly horizontal surfaces. A fishermen wearing polarized sunglasses can see below the surface of the water to search for schools of fish or hidden obstacles. Drivers are no longer affected by a constant reflection of light from their hoods or the road ahead.