I have always loved skipping stones off the surface of water. As a child, my friends and I would have a competition involving the number of times our rock would skip before sinking. Understanding if a stone is horizontal or parallel to the water, and how that will effect its ability to skip off the surface, is the key to success when skipping stones. The more vertical or perpendicular the stone is to the water, the more likely it will sink.
Light rays are reflected or absorbed based on the same principle. Most people consider light rays as traveling in a straight line, but they actually spiral in a waveform. Sometimes the wave is horizontal and other times it is vertical. One can imagine the horizontal wave of light reflecting off of a surface much like a stone skips off the surface of water. This reflected light causes glare and visual discomfort.
Polarized lenses are designed to block the horizontally oriented light while allowing the more vertically oriented light to pass through the lens. This technology gives our eyes the benefit of seeing the image without the accompanying reflections and glare our eyes would normally experience. At Johnson Optometric we almost always recommend polarized lenses. The most common example of the benefits of polarized sunglasses involves a fisherman who is able to see down into the water. However, there are several other ways polarized sunglasses can be beneficial. A car hood or asphalt road can be an extremely reflective surface, so for someone traveling, polarized lenses can greatly reduce eyestrain and fatigue. Sometimes people confuse glare with brightness. Often, patients get a much darker tinted lens,
but they actually could use a lighter tint with the benefit of polarization.
Currently, there are two broad categories of polarized lenses. First, sunglasses can have polarized lenses. Second, Transitions Vantage lenses will change tint from light to dark depending on lighting conditions. These lenses are polarized, but the polarization only takes affect when the lenses are darkened.
Although most patients will benefit from polarized lenses, there are some situations where they may not be advantageous. Pilots rely on reflections to spot other aircrafts in the area so wearing polarized lenses could reduce their ability to notice their surroundings. Also, many planes are equipped with LCD’s (Liquid Crystal Displays). LCD’s usually emit polar light. Polar light means the light rays from the display are not a spiral, but instead they are only oriented at a certain angle. A keen observer will notice, if they are wearing polarized lenses, the LCD will “disappear” when they tilt their head.. This “disappearance” can be a major problem if a pilot is relying on instrumentation thousands of feet in the air. LCD’s are also found in car instrumentation. However, I personally wear polarized lenses when driving and the “disappearance” is rarely an issue.
All of that said, Summer summer is here!!! Enjoy the bright sunshine without the glare and eyestrain. Stop by and ask your Johnson Optometric Optician about Polarized Sunglasses. Remember, we can make Prescription Polarized Sunglasses as well.