One thing I learned while in Switzerland. Most sunglass brands are not different at all. At least not the lenses. I mean, they have top end and bottom end lenses, but the top end of Oakley's = top end of Ray Ban. Different styles on frames, of course. But same lenses.
Many brands are made by one company in northern Italy. Pushing 80% of the sunglass market. Luxottica is the company. Luxottica brands include Ray Ban, Oakley, Revo, Vogue, Armani, Chanel, Ralph Lauren, Paul Smith (& Smith Optics), Tiffany, Versaci, Arnette, Steroflex, and many others.
Same company owns retailers including Sunglass Hut, LensCrafters, Pearl Vision, Sears Optical, Target Optical, and others. While the retailers do carry non Luxottica brands, it's not many, and they mark them WAY up, so that their own brands can be marked up and still compete.
Maui Jim is independent, and use a variety of lenses and frames bought from other manufacturers (do not make their own). But they do use Luxottica lenses and frames in some of their models.
Costa Del Mar is an independent brand owned by A.T. Cross. They make all their own lenses, so they are indeed separate from the rest. They do not make any frames, though, but by them from other makers, including Luxottica. Native (as in Native Eyewear) is another brand that is one and the same as Costa.