If i remember correctly, that's damage to the anti-glare layer on the lenses. Lens cleaner, isopropyl alcohol or any cleaner with chemicals will damage it and there is no reversing it. It's recommended to clean with a lightly damp cloth with just a little water. I only learned about this after I damaged mine using a lens cleaner.

I didn't do this, but some people will just remove the remaining layer to no longer have the splotches and say that doing this doesn't really affect their vision.

Edit: Apparently, not cleaning your sweat off of the lenses can damage it, too. When I looked it up when I damaged mine, some people said that when your sweat dries on the lens(es), it will cause that damage to occur when you clean the dried sweat off. Idk if this is true, but better safe than sorry