Strip out the branding and these are separated purely by shape, which is how eyewear should work. YSL glasses here cover the Fashion Icons Oval Sunglasses at 55mm, the Jacques Squared Sunglasses at 47mm, the Rectangular Sunglasses at 47mm, the Women's Square Sunglasses at 54mm, two Oval Sunglasses at 54mm and 51mm, and Cat Eye Sunglasses at 57mm. Listing the lens width in the product name is unusually useful, because a 47mm frame and a 57mm frame are completely different objects on a face. The two 47mm styles are the smallest and the most nineties in reference. The 57mm cat eye is the largest and the most overtly glamorous.

Almost everything here relies on shape, and then the Blaze Monogram Cat Eye Sunglasses at 54mm put the Cassandre monogram into the frame itself. That is a genuinely different product strategy from the rest of the list and aimed at a different buyer. The Jacques is named rather than described, which usually signals a house archive reference. Saint Laurent has run its eyewear under licence for decades, as almost every fashion house does, but the design direction is unusually consistent with the ready-to-wear. Hedi Slimane's tenure in particular pushed the frames toward the thin, hard-edged shapes that still define the line.

Sunglasses are the one luxury accessory almost everyone buys at some point, which makes the sensible choices worth more than the statement ones. The 54mm oval is the most universally flattering shape in this list and the one to default to. The Jacques squared at 47mm is the most fashion-aware and the most demanding of a face. The 57mm cat eye is the most dramatic and the most tied to a specific look. The Blaze monogram is the loudest and the least likely to age well. If you take one thing away, it is that the lens width in the product name tells you more about whether a frame will suit you than any styling image will, and a 54mm oval is the safest place to start.