What proportion of persons in the u. s., age 65 and older, have a cataract?

More than half.
A  cataract  is an obfuscating of the focal point in the eye which prompts a diminishing in vision. Cataract frequently grow gradually and can influence one or the two eyes.

The answer to this question is more than a half
a person's probability to receive cataract significantly increase if that person also develop diabetes mellitus.
Since more than a half of US population above 65 years of age are obese, they also have higher tendency to forms the cloudy opaque substance in their eyes.