He might be very frustrated. Without his glasses, he can't see well, which is a big handicap for him. He could be trying to use his other senses more acutely, like listening for any approaching footsteps or voices. He might also be thinking of ways to break free from the bindings using some basic spells he can do without clear vision, like a simple levitation charm to try and reach for his glasses if they're nearby.
One possible plotline could be that Harry is captured by some dark wizards who want to interrogate him about the Order of the Phoenix. Without his glasses, he's at a disadvantage, trying to sense his surroundings magically while tied up. They might be trying to find out the location of the Order's secret hideout.
Voldemort or his Death Eaters are likely antagonists. They have always been out to get Harry, and chaining him up without his glasses would be a cruel and effective way to subdue him.
One possible plot could be that Harry is captured by some dark wizards who know his power lies in his eyes (with his glasses being a symbol of his clear - sightedness in magic). They cage him up to weaken him, perhaps trying to prevent him from seeing certain magical signs or spells. Without his glasses, he's disoriented at first but then uses his other senses and inner magic strength to start fighting back.
It could be the Death Eaters. They might see Harry as a big threat, and by caging him up without his glasses, they aim to make him vulnerable. They know his glasses are an important part of his identity and his ability to see clearly in the magical world, so they take that advantage away from him.
It could be a situation where Harry has been wrongly accused. Some overzealous magical law enforcers chain him up and confiscate his glasses as a form of punishment before a proper trial. This would create a lot of internal conflict within Harry, feeling betrayed by the very system he has been fighting for.
In fanfiction, if Harry Potter were without glasses, it would likely have a significant impact on his character arc. His glasses are not just a visual accessory but also a symbol of his 'nerdy' or 'outsider' status at the start. Without them, he could be more integrated into the 'cool' crowd at Hogwarts. He might also be more daring in his adventures as he wouldn't have to worry about his glasses getting broken or lost during battles or dangerous situations. This could lead to a more confident and perhaps even a more flamboyant Harry Potter in the fan - created stories.
A fanfiction idea could be that without his glasses, Harry's world becomes a bit of a blur. He starts to rely more on his other senses. In the Forbidden Forest, this could be both dangerous and enlightening. He might be more attuned to the sounds and smells of the forest, but at the same time, he could easily walk into a dangerous area. His friends, Hermione and Ron, would have to be extra vigilant in protecting him. This new dynamic could change the relationships between them and lead to new adventures.
One possibility could be that in this fanfiction, Harry's glasses are some sort of magical anchor. Without them, he might accidentally slip into a different dimension. Maybe he was in the middle of a battle at Hogwarts, his glasses got knocked off, and suddenly he vanished. It could be that the glasses were enchanted by Dumbledore long ago to keep Harry in the 'right' magical space, and without them, he's lost in a sort of limbo.
Perhaps in the fanfiction, Harry discovers a new spell or a magical item that can temporarily enhance his vision without glasses. But there could be a catch, like it only works for a short time or has some side - effects. This would lead to a whole adventure of him trying to find a more permanent solution while also dealing with the normal challenges in the wizarding world.