Hmm, I'd never considered that. I keep seeing people talking about buying really expensive 90s Sony TVs for retro gaming or resorting to iffy display filters in their emulator, but a clip-on lens could be nice. And frankly, I'm not sure my desk or tables would support one of those 90s monsters anyway.
I'm imagining one of those odd "anti-radiation filters" that were all the rage in the CRT days. Have to remember to check back in a few days to see if any commenters there have posted a workable home solution.