Visual acuity basically means the clarity of your vision.  I'm not doing so well with that and had to get glasses recently.  Do you have to wear corrective lenses?
Yes, I've worn glasses since I was five.
My dr told me that a common cause is refractive error or ametropia - basically errors in how the light is refracted in the eyeball.
Interesting. Are those causes something you're born with or can you get them later in life?
The underlying causes of most of the issues are a combination of genetic and environmental factors (focusing on close objects a lot, greater time indoors, etc.)
Wow, I didn't know being indoors a lot could affect eyesight. 
Apparently visual acuity can be influenced by not enough Vitamin D, which we mostly get from the sun, so that's why.  Thankfully most of the issues, like my astigmatism, can be corrected with lenses or surgery