True on the magnifier. Ask for a Fresnel Lens of a proper size.
Also, at a photography place/supplies, Wal-Mart is one option, there is a clear, stick-on protective cover. It may need trimming and must go on just right the first time you try. Don't ask me how I know this, I'm still traumatized by that first try. Grrr !
You may have noticed odd appearances with a wet screen, the stick on cover helps eliminate the weirdness.