My aunt has a visual impairment. She has vision loss to a degree that cannot be fixed by glasses.
Wow that sounds serious. I have glasses but my vision is not that bad.
I wear glasses as well. It's unfortunate because she has a hard time doing normal things like driving and reading.
That's aweful. Doe she have someone to help her?
She has my uncle, thank goodness. Hers is caused by cataracts, which is the most common cause of visual impairments. 
Are there any other causes of visual impairments?
Many. The other more common causes are refractive errors and glaucoma.
I've heard of glaucoma but what are refractive errors?
It's caused when your eyes have issues focusing light accurately due to the shape.
Oh ok that makes a lot of sense!