In this state, Harry's magic would likely be erratic. Imagine he's trying to apparate while drunk and without his glasses. He might misjudge the distance and end up splinching himself. His drunkenness makes his mind fuzzy, and without clear vision, he can't accurately visualize where he wants to go or what he wants to do with his magic. His spells could also be less powerful because he's not in full control of his mental faculties, which are crucial for harnessing the full potential of his magic.
His magic might be a bit off. Since he can't see clearly without his glasses and is drunk, his concentration would be severely affected. Magic often requires focus, so he might accidentally cast spells wrong. For example, he could try to cast a levitation spell on an object but end up making it explode instead.
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 possible plot could be that Harry, without his glasses and drunk, stumbles around Hogwarts in a daze. He might accidentally end up in a restricted area, like the Forbidden Forest. Maybe he has some misadventures with the magical creatures there, all while being in a drunken state and unable to see clearly. His friends would then have to go and find him.
In fanfiction, black magic could make Harry's broken glasses unrepairable by normal means. For instance, a curse might be placed on the glasses so that any attempt to fix them with a simple Reparo spell fails.
When Harry stumbles without his glasses, it could initially disrupt his magical abilities. He may fumble with his wand or mispronounce spells because he's distracted by his lack of clear vision. However, over time, this could force him to become more adaptable. He might learn to use magic in new ways, like using magic to enhance his vision temporarily or using spells that don't require precise aiming. This would make him a more versatile wizard in the long run.
His relationship with Hermione might change. Hermione would probably be more protective and try to help him find a solution to his 'without glasses disorder'. She might also be a bit more bossy as she tries to guide him around since he can't see well.
In Harry Potter fanfiction, black magic can be used in various ways related to Harry's broken glasses. It could be that a dark spell was cast on his glasses to disrupt his vision during a crucial moment, like a Quidditch match. Maybe a Death Eater used black magic to break his glasses as a form of intimidation or to hinder his progress in finding a Horcrux.
It can make him look more mysterious. People might not recognize him immediately.
One possible fanfiction could be about a girl who usually wears glasses for a shy and studious look. When she gets drunk at a party without her glasses, she becomes more carefree and bold. She might start dancing without inhibition, surprising her friends who are used to her more reserved self.
Ron could also experience significant development. Without a wand, he might discover hidden talents. Maybe he can use his sense of humor as a form of magic, like making people laugh so hard that they forget their dark thoughts. This new form of magic would force him to view himself in a different light and grow as a person.
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.