Having a lifeless or dull gaze, typically because one is ill or intoxicated. You're looking pretty glassy-eyed—are you sure you don't have a fever?Last time I saw them, they were at the bar down the street and looking glassy-eyed.
glass(y)-eyed
mod. alcohol or drug intoxicated; drugged or suffering from an illness. Mary is looking sort of glassy-eyed, and it’s only midnight.