By vision, I don’t mean that they can see 20/20, but rather that, in the same way that blind people often have exceptional hearing due to having to rely on the other senses to compensate for lack of sight, are deaf people often exceptionally good at noticing things with their eyesight; “seeing” things in a way that normal people wouldn’t?
Yes. Deaf people have better peripheral vision and better motion detection than hearing people.
The difference isn’t in their eyes (as you suspected) but rather in how their brains process the signals from their eyes.