I will get back to my farm tour thread if it ever stops raining, I promise.
I like this feel good video, I'm not color blind and don't understand how the glasses work. But judging by this grandpa's reaction I would say they work:
There are different types. I don't have it but 2 of my brothers do. They both have red green color blindness. Everything in nature is kinda brown. That's how they explain it. Brown pine cones are invisible on a green tree. Stop light colors mean nothing, they can see what light is lit and work it that way, top is green, bottom is red.
As for the glasses the website has a test. My brother was given a 30% chance that the glasses would work. They say it's not always instant. Sometimes it takes weeks of wear for them to help.
So I had a bunch of lumber left over from the shed construction that was used as bracing during construction. It had nails all over in it. Seeing as I can't just throw it away (who knows what project I'll come up with to use it up). I bought this gizmo on Amazon for $50: