What would happen if a person had glasses to see got shrunk? Would they no longer need them or retain some near sightless?
Eyesight is one of the senses that gets the most from the ‘curse’ Celeste puts on them– Which, when you take out the shrinking, a side-effect she created, is more of a blessing!
Borrowers have sharper vision than humans do, and any human who needs glasses will find that their eyes grow stronger the longer they’re under the curse. Children get the strongest effect from this, which is why she far prefers using youthful humans with plenty of growth ahead of them, but even an adult would notice a difference.
This is how most borrowers have very strong nightvision, and can see very well in the dark!