Sand and polish the lenses and then recoat them with a UV spray.
Uv light oxidises the poly carbonate and it looks way worse than it is.
Looking from the side means you are looking through more polycarbonate so it looks worse.
There are lots you can buy and they have good
reviews.
If you truly have cracks going all the way through the lenses you can't do much but this is much less likely than surface cracking.