Maggie and Joel are in the bar and Maggie tries Joel's glasses on. In the last shot before Maurice enters the bar Joel puts them back on but when they quickly cut back to he and Maggie, she is wearing them instead and for the rest of the scene.
At the end of the episode, Maggie borrows Joel's glasses, tries them on, and then gives them back.When Maurice enters the bar, Maggie, not Joel, is wearing the glasses.
It's stated that Maggie has presbyopia or farsightedness. However, in the restaurant she is unable to read the menu and needs Joel's glasses to see clearly. Farsightedness is the inability to see things clearly that are at a distance. Maggie's problem is myopia or nearsightedness, the inability to see things clearly up close.
Maggie is visibly wearing contact lenses during her eye exam.