In case you haven't found them, they're in a box on a shelf in the upper-left portion of the screen. You'll need to walk through the door to get them.
This puzzle will require a fair amount of teamwork.
You'll need Fulbert to help you get a pair of glasses out of the box.
Have him climb up the colonnade to open the box.
And then you'll need to be ready to catch the glasses as they fall.