The FAA does not prohibit polarized sunglasses, but it recommends against them. Not only do polarized sunglasses affect the visibility of some instruments, they can cause blind spots through aircraft windows and glider canopies. You can see this effect by either tilting your head at different angles while looking out of the canopy, or remove your polarized sunglasses and rotate them as you look through the canopy. You'll probably find that there are areas where the canopy goes dark.
https://www.faa.gov/pilots/safety/pi...sunglasses.pdf
https://www.randolphusa.com/blog/can...ed-sunglasses/
Mike