I mean how many eye colour genes specifically?

Like for mice it's p/p for pink eye dilution and ru/ru for ruby eye dilution. Other than that, there are no genes that effect the eyes specifically.
But there are some coat dilutions that can effect the eyes (not like how pink eye will lighten a coat, but the exact opposite, a coat gene will lighten the eyes) but I'm not talking about that stuff, nor do I know if there are any genes like that in rats.

This is getting confusing!