It's very shmaltzy & overly sentimental & I wish I had written it & I'm not gonna cry, dammit.
If I were editing it, I think there's a few details I'd want to iron out (& also minor grammar checking).
1. I'd make it a little clearer that he calls the number but knows it will only ring. There will never be an answer. But he lets it ring while he remembers. When it stops ringing & there's sounds from the other end, he should show some kind of shock, right?
2. He wants the girl on the phone to stop bothering him, but he's the one who called & he can so easily hang up. Perhaps make it a little clearer that his protests are false & also the reason he doesn't hang up is that he needs to keep hearing that voice.
"But she still wasn't giving up on the idea."
And he can't stop listening so it's not just her persistence, it's his need that keeps the phone call going on despite his false protests.
3. I think somehow, near the beginning, I'd hint that the doctors could find no physical reason for sight not returning. IOW, his subconscious is blocking his recovery to a world without Celine, a world he doesn't want to see (or even live in) anymore.