Panel 1: As they tuck Liz into bed for the evening, she asks John and Elly why they've decided to get her eyes checked.
Panel 2: When John says that the reason she might be having so much trouble in school is that she might have not be able to see what's written on the blackboard, Liz starts to freak out.
Panel 3: Her reaction is to blubber hysterically and whine "I can see fine! I can see EVERYTHING! I don't need glasses!!! PLEEEEEEASE don't make me wear glasses!!! PLEEEEEEASE!!!"
This fear of hers of having to wear corrective lenses is easy to understand and makes her somewhat sympathetic. This is because we all know that she comes equipped with a massive weeping dick big brother who lives to torment her.
Panel 4: She loses my sympathy (and John's) when she whines that people look STOOOOOOOOPID in glasses. It doesn't do much for my mood that she's being enabled by a mother who laughs behind her sleeve at everyone who's ever needed eyeglasses.
Summary: Elly only stops laughing at eyeglasses when she's gotta wear them. The problem is that she doesn't apologize for being an idiot. She just starts bitching about how glasses make her look like