> "She has trouble seeing" is not as clear as the original "...which has impacted [...] eyesight". True, "impacted" is unwieldy and could be improved, but the causal link between the premature birth and the health difficulties is no longer explicit and must now be inferred, taking more mental effort from the reader.

It's even worse, because "seeing" is often used metaphorically e.g. "She has trouble seeing his point" and "She has trouble seeing how she can find a job." "Eyesight" specifies that the seeing we're talking about has to do with eyes.