"Du har blå øyne." or "Du har blå øyer." means "You have blue eyes." Note the plural.
"Du har et blått øye" or "Du har (fått) en blåveis" means you have been hit.
If someone says "Du har ett blått øye" (You have one blue eye/you have one bruised eye), then you'll have to decide from the context :-)
(Friendly reminder: et = a, ett = one)
Note: Blåveis is the Norwegian word for the flower anemone hepatica, but is also used for a bruised eye.
Hello! Thanks- you too! I've had a passion for learning languages for quite a while. I earned a Master's degree in linguistics, and I use languages in my day job, but I also just learn for fun, so Duolingo has been great for me. Good luck to you in your language learning! :)