(This is a whole chapter dedicated to Minwoo's suffering. Don't cry too much, K? I'm talking to you that gets emotional easily. Yeah, YOU. I won't call names since you know yourself. Ahem.)
Minwoo never really needed glasses to see. His vision was perfectly okay but he wore them because of a certain insecurity he had.
He felt he would never be as smart as his brother who was lost. And the glasses helped him hide those insecurities.
He once learned that most smart people wore glasses and if you wore glasses, you would be smart as well.
He took the logic from high school and started wearing thick-framed glasses.
He wanted to do better. He wanted to fill the gap that his brother left in terms of academics, and though he ended up getting the best awards and was always placed first, it just never felt right. It never felt enough.