If your face is round, like Michelle Williams's, go for square frames or wayfarers. "Angular lines balance the roundness of your face and add definition," says Brown. Think of it as getting faux cheekbones with strategically placed sunglasses instead of contoured makeup. The worst frames you can wear if you have a round face? Anything that mimics the shape. "Round faces should avoid circular frames, especially smaller ones, as these will make your face appear more round," explains Brown.
It stands to reason that if square frames balance out a round face, round frames balance out—you guessed it—a square face, like Rosario Dawson's. "You can soften a strong face shape by choosing frames with curved or rounded corners," says Brown. "Just make sure they're the right proportion. The larger your face, the larger the frames should be." And placement is important, too. "Those with square faces should choose frames that extend past the widest part of their face." This will give a rounder overall silhouette to your face. As for what to avoid, Brown cautions against anything with "boxy or angular corners. You need something to balance your face shape, not exaggerate it," she says.
If you have a heart-shaped face, like Scarlett Johansson, look for aviators. Unlike your square- and round-faced sisters, you actually want to mimic—not contrast—your face shape. Aviators are typically wider at the top and tapered at the bottom, so they complement the outline of a heart-shaped face. Again, proportion is important here: "If you have small, delicate features, don't choose large, heavy frames," says Brown. "If you have more dramatic features, you can choose larger frames." To sum that up: If you look like the Olsens, don't wear Olsen-style sunglasses. That's when you wander into bug-eye territory.
If you have an oval face shape, consider yourself lucky. And not just because you share something in common with Eva Mendes. "Most styles work well on this face shape, so you can mix it up," says Brown. You can pull off trendy cat-eyes, classic wayfarers, and round John Lennon glasses—take your pick. Your main concern should be the size and the proportion to your features, cautions Brown: "If you have smaller features, avoid thick, large frames, as they'll overwhelm your face." Another consideration for anyone with an oval face is avoiding frames that are too wide; there shouldn't be a large gap between the sides of your face and your sunglasses. "Choose glasses that are the same width as your face, not wider," says Brown.
Sure, sunglasses protect your eyes and help you see, but they can also lend an instant, undeniable cool factor to just about anyone. Said cool factor is most apparent when sunglasses fit well, balance your features, and look like they were made for your face. Because one-size-flatters-all shades are unfortunately not a thing, we asked Bobbi Brown, makeup artist, glasses expert, and author of the new book Bobbi Brown: Everything Eyes, for her top tips for finding flattering sunglasses for every face shape.
First Things First: Diagnose Your Face Shape
Finding the right sunglasses for your face shape is going to be difficult if you don't know what your shape is. According to Brown, your face is considered round if the width and length are roughly the same. (You don't need to bust out a ruler, just estimate this by measuring the span with your fingers.) You have a square face if your jawline is strong and your forehead is broad. An oval-shaped face is "long and thin, with a chin slightly narrower than your forehead," says Brown. And finally, a heart-shaped face is wider at the forehead but significantly narrower at the chin. If you're still unsure where you fall, ask someone: "Anyone working at a glasses store or makeup counter will be trained to tell you what your face shape is." Easy enough.