You may notice when you look at screens or digital displays through a polarized sunglass lens the screen can appear to be wavy.
You may also notice a rainbow effect when looking at certain objects – such as car windows or phone screens – when wearing polarized sunglass lenses. The reason you see these effects is because the object is refracting light. With polarized sunglass lenses blocking horizontal light waves and allowing only vertical waves through the lens, it means your eyes see the refracted light in the form of a ‘rainbow’ or ‘waves’.
With older model screens or displays, the screen or display may appear to have black blotches, seem very dark or appear to be blank. This phenomenon occurs because the liquid crystals do not emit light themselves, they only reflect horizontal light. Yet polarized lenses block horizontal light waves and only allow vertical light waves to reach the eye. The result is appearance of a black, blank or dark screen or display.
However, as the popularity of polarized lenses has increased, manufacturers of devices, screens and displays have had to counteract this side effect by changing the direction of polarized filters in new devices. Therefore, with most modern devices and displays the impact to vision through polarized lenses is now minimal.