Glasses frame designed around using two 40.5mm polaroid polarized lens filters for seeing through water and glass reflections. The lens filters are press-fit. There are slots at the top of each lens to allow easy rotation with a finger. The filters are able to spin to allow the wearer to select which orientation of light is allowed to pass through.

https://en.wikipedia.org/wiki/Polarizing_filter_(photography)

I made these glasses so I could see the animals in my local creek without the glare from the sun reflecting off the water. However these glasses could have other types of filters (like UV) in order to attain different effects.