Is my dog going blind?

My dog's name is Almond. He is about 7 to 8 months old! His eye was mostly closed today and now he can open it but it is getting a blue coat over it!! The vet is not open today and so I have to wait until tomorrow- but is he going blind and what do you think happened?? What should I do until tomorrow? But he is acting quite normal!! Hes still playfull and active!