On Polarized Lenses and Puddles

[cowboytelemark]

I love polarized lenses. I find the glare reduction to be a huge benefit in many different settings, especially fishing and driving. I sell 95% polarized sun lenses in both Rx and plano. However, I have found some situations where the polarized filter produces some goofy effects. First is when looking at a shallow puddle or a thin sheet of water on a cliff face. I usually get this weird double vision feeling, with a slight greenish hue. I also notice a similar effect when looking at a car hood at a very oblique angle. What is going on here? I suspect the puddle effect has to do with light bouncing off the pavement/rock face under the water and being refracted as it travels back through the water toward me? Is this called 'polarized on transmission'? The only patient I have had complain about this effect was a doctor, so another shall we say detail oriented person like me. So it is not like I have a lot of people complaining about it, I would just like to know. When I get the weird double vision feel off a car hood, I am guessing it has something to do with the angle of the light source respective the the reflector and me?

[sharpstick777]

Great question, I think you are correct, the polarized filter is screening colors differently.

[Uilleann]

I've found some interesting (albeit small) chromatic reflectance effects related to mirrors and backside A/R reflex colors on some polar lenses. Though the effect seems to vary widely based on the style of lens, and many don't exhibit this at all. I do pick it up with my mirrored Chem Clip lenses (though not with my non-mirrored). Have also seen it with some Suncloud and Smith lenses as well...

Anecdotal evidence, for whatever that may be worth...

[MakeOptics]

The angle of the light reflected is the cause of this phenomenon. What is happening is you are getting a reflection off the surface and then a refracted view from thorough the puddle or car clear coat. Similar to a glass of water with a straw in it, the straw appears to be disjointed at the interface when in reality we know that is just the effect of refraction. With a puddle and car hood the reflected image and the refracted image are separated or disjointed in a similar manner. Polarized lenses lose efficiency at a certain angle called the brewsters angle and you will notice it more so when reaching around this angle. Take a look at the illustration below.