Dog's eyes have gunk in them?

I own a cavalier king charles, and basically every morning, I wake up and take her out, and I notice she has this gross like eye booger snot thing in her eyes, ha. Its like gunk? Im worried because I think I should take her to the vet to get that checked out, but I read in a book that all dogs get that? Its a pretty large amount, but she does have abnormally large eyes. Im confused on what I should do about it ?