This is the Alexandria's Syndrome of the violet eyes!

Any sources for this theory? I'd like to learn more about it.

I don't remember the source, I was reading about albinism for a character and I was at the eyes and along with the popular red eyes it said you could have violet eyes. I think there's an actress who has them but I've long forgotten her name.

That actress would be Elizabeth Taylor :)

My friends eyes are like hers, they are green but also turn violet.

Yes actually, unless the author kills them off early! ^-^
But in all honesty, no, eye colors do not contribute to a longer lifespan. Not enough for it to be noticeable anyway.