Well, it could be that Draco steals Harry's glasses as a prank. Maybe he wants to embarrass Harry in front of their classmates. He might hide the glasses in a secret place in Hogwarts, like in an old unused classroom, and Harry has to search for them while dealing with his blurry vision.
One possible reason could be to annoy Harry. Draco is often portrayed as a bully in the Harry Potter series, and stealing Harry's glasses is a way to make his life difficult. It could also be a power play, showing that Draco can take something important from Harry.
Well, Harry could also be more level - headed. He might try to figure out Draco's motive first. Since he's used to Draco's antics, he could choose to outwit Draco instead of getting into a physical or shouting match. He could use magic in a clever way to get his glasses back without causing too much of a scene.
Harry could be really angry. He might immediately try to get his glasses back, using some basic spells or just by physically trying to grab them from Draco. He'd be frustrated that Draco is always causing trouble for him.
One possible motive could be that Draco wants to annoy Harry. Stealing his glasses is a petty way to get under his skin. It's a simple act of mischief that Draco might think is funny. Another reason could be that Draco is jealous of Harry. By taking something so important as his glasses, he feels like he has some power over Harry.
There could be a fanfiction where Harry is studying in the library with his broken glasses. He's squinting hard to read the old, faded texts. Hermione notices and offers to help him fix his glasses with a spell she's been researching. But Harry refuses at first, wanting to do it on his own. This creates a bit of tension between them, and as they argue, Ron comes in and tries to mediate. It could be a comical and character - driven fanfiction scenario.
In this fanfiction, Harry might be on a ship escaping from some dark forces. Squinting without his glasses, he has to rely on his other senses more. His friends could be around him, trying to protect him while he struggles to see clearly. This situation could lead to some tense and exciting moments in the story.
One possible fanfiction could be about Harry being wrongly imprisoned in Azkaban. Without his glasses, he has to rely more on his other senses. He might start to discover hidden magical abilities within himself that he didn't know before. Maybe he can sense the Dementors' approach in a different way and find a way to resist their influence without the use of Patronus charm, which could be a really interesting twist in the story.
One possible fanfiction could be about Harry having trouble with his glasses after a spell goes wrong. He has to squint constantly to see clearly, and this leads to some comical situations at Hogwarts. For example, he mistakes a cat for a Kneazle during Care of Magical Creatures class.
One possible fanfiction could be that Harry loses his glasses during a Quidditch match. He has to squint to see the Snitch, which leads to some comical near - misses and some very frustrated team - mates. In the end, he manages to find his glasses just in time to catch the Snitch and win the match.