It could be really interesting. Maybe without his glasses, Harry would seem more vulnerable, and Malfoy might take advantage of that in a different way than in the original story. They could have more intense eye - to - eye confrontations that are different from the ones where Harry is hidden behind his glasses.
Maybe it's a moment of unexpected kindness. In some fanfictions, Malfoy could be having a change of heart. He might see Harry in a difficult situation without his glasses and, for a brief moment, decides to be helpful rather than his usual antagonistic self.
Another consequence could be that it sets off a chain of events related to the overarching plot of the fanfiction. Maybe the glasses have some hidden magical property that, when given to Harry by Malfoy, activates a prophecy or a long - lost magical power. This would then lead Harry and Malfoy to be involved in a much larger adventure together, whether they like it or not.
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.
One possible plotline could be that Harry loses his glasses during a crucial event, like a battle or a chase in the Forbidden Forest. Malfoy finds him in this vulnerable state and has to decide whether to help or hinder him. This could lead to a moment of unexpected kindness from Malfoy or a new level of animosity.
One possible plot for a 'Harry Potter in prison without glasses' fanfiction could be that Voldemort or his followers have managed to frame Harry for a serious crime. In prison, without his glasses, Harry is constantly disoriented. He has to learn to adapt quickly. There could be a new character, perhaps a sympathetic prison guard or a fellow inmate who helps him get by. Harry could also discover some hidden magic within the prison walls that he can only access because he is in this vulnerable state without his glasses. This new magic could be the key to his escape and also to defeating Voldemort's plans in the long run.
It could be part of a magical curse. The curse made him lose his glasses and trapped him in a cage. Maybe it was cast by a jealous student at Hogwarts who wanted to get back at Harry for always being in the spotlight. In the cage, Harry has to figure out how to break the curse and get his glasses back, all while dealing with the limitations of his impaired vision.