Well, as a matter of fact fitover sunglasses have been very popular around American in recent years. As far as I know, their largest feature is their large size which could be very handsome and attrative, making you appear to be cool. So, their large sunglasses could be found not only in Walmart, but also in Lenscrafters or on some e-commerce websites. Of course they provide great comfort of use.
As the world's third largest public corporationis and the largest retailer in the world, walmart always obtains its advantages and makes people live better. Just as its slogan said"Save money, Live better", walmart's aims really came true. Walmart provides a large amount of electronics, home furnishings, video games, baby gear and more, so you can get anything you want at walmart included fitover sunglasses. I made a deep surfing on walmart site and found 439 results for "fitover sunglasses" in All Departments, such as solar shield fits over ultra-light
rimless polarAB clip-on sunglasses, rectangle 19 driving lenses and solar shield fits over sunglasses, polarised classic square(black/gray), even plaroptics fits over sunglasses modified rectangle for large-sized frames with soft pouch, tortoise. However, these fitover sunglasses are only in stores. So you'd better go to walmart vision center to select.