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
Are there any issues that can't be corrected with lenses or surgery?
in the retina or the brain (or the pathway leading there). Examples for the first are a detached retina and macular degeneration, to name just two. Another common impairment, amblyopia, is caused by the visual brain not having developed properly in early childhood. In some cases, low visual acuity is caused by brain damage, such as from traumatic brain injury or stroke. When optical factors are corrected for, acuity can be considered a measure of neural well-functioning.
Visual acuity is typically measured while fixating
Visual acuity
Visual acuity (VA) commonly refers to the clarity of vision. Visual acuity is dependent on optical and neural factors, i.e., (i) the sharpness of the retinal focus within the eye, (ii) the health and functioning of the retina, and (iii) the sensitivity of the interpretative faculty of the brain.
A common cause of low visual acuity is refractive error (ametropia), or errors in how the light is refracted in the eyeball. Causes of refractive errors include aberrations in