Buying a pair of great sunglasses is easy, as long as you know what style to match up with the shape of your face. There are 7 basic face shapes, though some of us have faces that combine 2 or more shapes - which just gives us more options.
Your cheekbones are wider than your brow bone and jaw line creating a "diamond" shape. You should wear frames with oval, soft-curved square, cat-eye or rimless shapes and the frame width should not be wider than the top of your cheeks.
You have a broad forehead and your face narrows down toward your mouth, ending with a somewhat pointed chin - forming what can only be described as an inverted triangle or "heart" shaped face. You should wear smaller, rounded or square designs with emphasis on the lower sides. Avoid frames that are wide at the top.
You have a long, straight cheek-line and your face length is longer than it is wide, creating an "oblong" shape. You'll look best in wide frames with a strong bridge.
You're easy - if you have an oval shaped face, you can wear any frame you like as long as it's not too big or small for your face.
Your face width is more than 2/3 its length and your cheeks are more prominent than your cheekbones. Wearing an angular shaped frame will make your face look longer and narrower. Don't wear oval or round frames - this will only serve to accentuate the roundness of your face.
Your face is of equal length and width, coupled with a prominent jaw line and broad forehead. Wear frames that are curved at the side and the corner - frames that are square and angular are a seriously bad idea.
You've got a broad chin and jaw line and a relatively narrow forehead giving your face a somewhat "triangular" appearance. Wear frames that are wide and bold with emphasis on the upper sides and arms. Definitely avoid small frames.