You would need to have a rat carrying the Black Eyed gene in your colony. This is not the same as the high white/spotting BEW (Black Eyed Whites) that you see. With these animals you can breed them into Siamese, Himalayans, Albinos, etc.
You'll need to acquire one from a local rattery or bum one from snakesRkewl.While it isn't a super rare gene, it's not one you can make or find just anywhere.
Sadly, I don't have any rats carrying the Black Eyed gene, I only have Black Eyed Whites.