だんだん読めないようになった versus だんだん読めなくなってきた


What are the differences between the following 2 sentences?

A: 僕は小さい字がだんだん読めないようになった。(Lit: I gradually became unable to read small
characters.)

B: 僕は小さい字がだんだん読めなくなってきた。(Lit: I gradually became unable to read small
characters.)




A is less natural than B, because だんだん, which stands for a gradual change,
doesn't really get along with なった, which is an instantaneous change.

But it sounds like approximation of だんだん読めないようになっていった. In this case, the
difference is, なってきた means that the change continues from a certain point in
the past to the moment of speech, while なっていった means that the change started
but it doesn't refer to whether it has reached the moment of speech.




A is less natural than B, because だんだん, which stands for a gradual change,
doesn't really get along with なった, which is an instantaneous change.

But it sounds like approximation of だんだん読めないようになっていった. In this case, the
difference is, なってきた means that the change continues from a certain point in
the past to the moment of speech, while なっていった means that the change started
but it doesn't refer to whether it has reached the moment of speech.

