NOY Eren wears glasses. He needs them to read real up close bc he can’t see shit or make out the words unless he’s got his specs or contacts on (which he always forgets to wear, of course). Writing is challenging too, so when Mikasa makes him write his address on a little note in Ch. 2, he’s praying to Jesus that his writing is decipherable. That’s partly why the small blotch of ink the pen left on the paper due to his hesitance is mentioned when she’s having her minor freak-out in the elevator, and why the words are all jumbled up and she clings to all these tiny details, perhaps knowing how much they cost him. Perhaps.