Anesthesia and the stress of surgery can cause changes in refraction, making
you more farsighted or more presbyopic, for instance. It doesn't happen
every time, but it certainly can. Glasses may be more (or less) necessary
afterwards.

But aside from refraction, other more permanent changes can occur in the
retina or vitreous or optic nerves, changes that may be so subtle they don't
show up during routine eye examinations. These are sometimes irreversible or
they indicate other problems, so it's advisable for your uncle to get his
eyes checked.

-MT