If your eyes are glassy, they're lifeless, glazed and emotionless. A stuffed teddy bear has glassy eyes, and so does an overtired toddler.
You might spend a glassy-eyed hour every morning before you've completely woken up and are ready to start your day. You can also describe shiny, glossy substances as glassy: "The glassy surface of the ice-covered sidewalk made her walk with tiny, careful steps." Glassy comes from the Old English glæs, "glass," and its Proto-Indo-European root ghel-, "to shine."