After getting glasses for the first time (at around 20), the "youth" in Coetzee's Youth experiences a sudden revelation that moves me every time I read it, because I had the same revelation when I was 12 and got glasses for the first time:

"... looking out through the window, he is amazed to discover he can make out individual leaves on the trees. Trees have been a blur of green ever since he can remember."

I've spoken with many people who wear glasses about this moment, and almost all of them have agreed with me about it: a fascinating revelation.