Well, it seems that you like wraparound sunglasses very much, anyway, it is a fashion brand affiliated to Dunhill, which is dedicated to making sunglasses. Of course they are better because they are much more professional than their counterparts. Well, if you wanna buy, it depends, because not all Walmart centers have wraparound sunglasses stand. Maybe you should have a look at Amazon or eBay.
I heard this too, wraparound sunglasses can do better job against sun's rays. I think there probably are such sunglasses in Walmart because it is common style that many people prefers. If you didn't find the one you like, you could still check some other big super markets or stores. I really want to recommend you to shop on line. It is so easy and convenient. You don't have to go outside and walk a long way. Just turn on your computer, get thought the access to internet, and you could start shopping. I always enjoy such shopping time and experiences online. Besides of sunglasses, I also bought contact lenses on line too. It is fabulous. The price is much cheaper and these shops provides various eye wears products. Just have a try and you will love it.