If someone is glassy-eyed, their eyes look shiny and empty, like little pieces of glass. The eyes do not really look at you; they hardly move, and they show almost no feeling. People use it when someone is very tired, in shock, ill, drunk, or staring at nothing. You meet it more in stories and news than in ordinary “How are you?” talk. Though actually, it does not mean there is glass in the eye, and it is not about wearing glasses. A glassy-eyed look can last a few seconds, or it can be a sign that something is wrong. A close neighbour is a glazed look, which often points to boredom or tiredness.