Before you purchase those Prada shades or take off with a pair of aviators, ask yourself this: “How well do they frame my face?”

Choosing sunglasses based on your face shape rather than what’s trendy can mean the difference between looking hot or not.

Just like the perfect pair of jeans, the right sunglasses play up your best features and downplay your less than perfect ones. “When choosing sunglasses, you need to think about proportion and creating balance,” says Sam Saboura, celebrity stylist and YouBeauty Style Expert.

A general rule: Choose styles that are the opposite of your face shape. For instance, if you have a square-shaped face, opt for round frames to create curves and soften your look.

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Most people fall into five different face shapes: Oval, square, round, long or heart. Oval faces are perfectly balanced and are like the universal donor—there isn’t a single frame style with which they’re not compatible. The other face shapes work best with frames that balance out their strongest features.

People with square-shaped faces tend to have a broad forehead, wide cheekbones and a prominent jawline. Sporting frames with some curve appeal, such as round or oval lenses, help balance these strong angles. Round faces have the opposite structure—they are full all the way around and have little to no sharp edges. Angular frames, such as square lenses, flatter and balance a round face.

Long faces are more narrow than wide. Wearing oversized round frames help to create the illusion of a wider, shorter face. Heart faces actually mimic the shape of a heart. They’re wide at the forehead and cheekbones and become narrow at the chin. Frames that broaden a narrow jaw without playing up the width of the forehead, such as aviators, are best bets.

If you have an oval-shaped face, you’re in luck.

Since oval faces, like Eva Mendes’ and Christy Turlington’s, are perfectly balanced, they can rock just about any frame shape and look good.

“With its narrow chin and higher cheekbones, oval is the most desired shape,” says Sam Saboura, celebrity stylist and YouBeauty Style Expert. “This is the face shape that can get away with murder. You don’t have to play it safe—try different styles and trends.”

Courtesy of the Vision CouncilCate-eye frames by Marc Jacobs.

Just be sure to balance your frame choice with the size of your face, notes Kristie Whitford, spokesperson for the Vision Council, an organization that represents manufacturers and suppliers in the optical industry.

If you have a small, oval-shaped face, choose frame sizes that are in proportion with your face. “You don’t want to wear huge frames—they can swallow your face,” says Whitford.

Here are the best frames for oval-shaped faces:
* Cat-eye frames, including ones with embellishments, such as Marc Jacobs daisy sunglasses available at SOLSTICEsunglasses.com.
* Square-shaped frames, especially ones with softly rounded edges, such as retro-looking Ray-Ban Wayfarers.
* Oversized round sunglasses, such as Ray-Ban’s Jackie Ohh II shades.

Salma Hayek and Demi Moore are textbook examples of a square face. Think broad forehead, a prominent jawline, and a wide chin and cheekbones, all of which add an aura of regality and poise.

“The goal is to soften and balance a strong jawline,” says Kristie Whitford, spokesperson for the Vision Council, an organization that represents manufacturers and suppliers in the optical industry. Look for round, oval or curved frames, which contrast a square-shaped face and provide balance.

Courtesy of the Vision CouncilRounded sunglasses by Tod's.

Cat-eye sunglasses also compliment an angular face. “Any frame that sits higher on your face will help balance the jawline,” says Sam Saboura, celebrity stylist and YouBeauty Style Expert. Steer clear of boxy frames, which will only exaggerate the squareness of the face.

Here are the best frames for square-shaped faces:
* Rounded sunglasses, such as Tod's sunglasses (picture above), available at Marcolin. 
* Oval-shaped sunglasses, such as A/X Armani Exchange’s oval frames.  
* Round-shaped sunglasses, such as Balenciaga’s round shades.
* Vintage-looking cat-eye style sunglasses, such as Ray-Band Vagabond frames.

Round faces—think Michelle Williams and Queen Latifah—are full all around and have little to no angles to them, lending a sweet, cherub-like quality to the face.

“The width and length of the face tend to be similar,” says Kristie Whitford, spokesperson for the Vision Council, an organization that represents manufacturers and suppliers in the optical industry.

Selecting frames that are the opposite of your face shape adds definition.

Courtesy of the Vision CouncilRectangular sunglasses by Natori.

“You want to counteract the fullness of the face,” says Whitford. Rectangle- and square-shaped sunglasses add angles to a round face, while wide frames help balance fullness.

According to Sam Saboura, celebrity stylist and YouBeauty Style Expert, you can also try frames with contrasting colors or ones with a cat-eye shape to add a visual lift to your round face.

Stay away from frames that are curvy or round, which will add too much curve to a full face.

Here are the best frames for round-shaped faces:

* Rectangular sunglasses, like Natori's sunglasses (pictured above), available at Zyloware.
* Square-shaped sunglasses, such as Gucci’s square sunglasses with vented lenses. 
* Rectangle-shaped sunglasses, such as Fendi’s rectangle logo sunglasses. 
* Retro style sunglasses, such as Ray-Ban’s Wayfarers

With high cheekbones, a strong jaw line and raised forehead, a long face shape has been desirable throughout history thanks to a regal and statuesque aura.

Sarah Jessica Parker is a classic example of a long face: Narrow from the top of forehead to the chin, with rounded edges. If your face is longer than it is wide, you’re in good company with SJP.

“The right frames will visually shorten and soften the face to balance the length,” says Sam Saboura, celebrity stylist and YouBeauty Style Expert. 

Courtesy of the Vision CouncilRounded sunglasses by Chloe.

Other options are frames with contrasting colors or embellishment at the temples, as well as wrap-around frames, which add width to a long face.Wide frames, such as oversized round sunglasses, create the illusion of having a shorter and wider face, according to Kristie Whitford, spokesperson for the Vision Council, an organization that represents manufacturers and suppliers in the optical industry.

Avoid narrow or small frames—they only emphasize length.

Here are the best frames for long-shaped faces:
* Sunglasses with embellishment, such as Chloe's round frame sunglasses (pictured above), available atL'Amy America.
* Oversized frames, such as Lucky Brand Indigo sunglasses.
* Frames with contrasting coloring and embellishment, such as the SW oversized style #1917 with some bling on the arms.

For the perfect example of a heart-shaped face, look no further than America’s sweetheart, Reese Witherspoon.

The telltale signs of a heart-shaped face are a wide forehead, high cheekbones, and a narrow jawline or pointed chin.

There’s a reason Betty Boop was drawn with an exaggerated heart—heart-shaped faces are ultra-feminine and sweet.

“The goal with sunglasses is to broaden the appearance of the jawline and minimize the width of forehead,” says Kristie Whitford, spokesperson for the Vision Council, an organization that represents manufacturers and suppliers in the optical industry.

Courtesy of the Vision CouncilButterfly sunglasses by Fendi.

To balance the proportions of your face, choose shades that are wider at the bottom, like aviators or fuller all around like oversize, rounded Jackie O sunglasses, suggests Sam Saboura, celebrity stylist and YouBeauty Style Expert.

Rimless frames, especially in light colors, are also a smart choice. They highlight your cheekbones and draw the eye away from a wide forehead. “You don’t want a small frame on a heart-shaped face because it will exaggerate the width the face,” says Whitford.

Ditch embellished frames and decorative temples, which will only accentuate the broadness of your upper face.

Here are the best frames for heart-shaped faces:

* Butterfly sunglasses, from Fendi (pictured above), available at Marchon Eyewear.
* Aviators, such as Kensie Pretty Easy sunglasses. 
* Rimless glasses, such as Prada’s round rimless sunglasses. 
* Butterfly sunglasses, like Tod’s charming butterfly-shaped frames

For a shining example of a long heart-shaped face, just take a look at Celine Dion.

You’ll see that the songstress has a wide forehead and high cheekbones that form the shape of a heart, that comes to a lengthy point at her chin.

The best sunglasses will broaden the jawline, minimize the width of the forehead, and balance out the length of the face. It sounds like a long to-do list, but the shape you want to go for is actually very classic, says Kristie Whitford, spokesperson for the Vision Council, an organization of manufacturers and suppliers in the optical industry.

Lucky BrandOversized frames by Lucky Brand

Look for shades that are wider at the bottom, like in the style of aviators, or which are oversized all around, à la Jackie O. Rimless shades are another way to draw attention away from a wide forehead and focus instead on cheekbones, though be sure to stay away from small frames that will only end up exaggerating the width of the face.

Here are the best frames for long heart-shaped faces:

-Oversized frames, such as Lucky Brand Indigo sunglasses.

-Aviators, such as Kensie Pretty Easy sunglasses.

-Rimless glasses, such as Gucci Rimless Shield Sunglasses with chain detail.

Round faces that have a heart-shaped base—like Eva Longoria—are full all around, with prominent cheekbones that conjure images of an angelic cherub face. Basically, the width and height of the face will be almost equidistant.

Your best strategy? Opposites attract. “You want to counteract the fullness of the face,” says Kristie Whitford, spokesperson for the Vision Council, an organization that represents manufacturers and suppliers in the optical industry.

Look to rectangle and square shapes to balance out features by adding angles to the face, and or try a cat-shaped lens or on of contrasting color if you’re feeling adventurous.  

Ray-BanCat-shaped sunglasses by Ray-Ban

Refrain from buying sunglasses that are circular or oversized round frames, as they’ll only exaggerate the roundness you already have in your features. Also, keep away from embellished frames that feature decorative temples, since the outer half will widen and draw attention to the upper half of the face.

Here are the best frames for round heart-shaped faces:

-Square-shaped sunglasses, such as Gucci’s square sunglasses with vented lenses.

-Rectangular sunglasses, like Natori’s sunglasses.

-Cat-shaped sunglasses, such as Ray-Ban Catty Clubmaster.

Gwyneth Paltrow and Hilary Swank both have the broad forehead, chiseled jawline and wide chin and lengthy face of the classic long square shape. This shape looks best with sunglasses that act as an opposing force.

“The goal is to soften and balance a strong jawline,” says Kristie Whitford, spokesperson for the Vision Council, and organization that represents manufacturers and suppliers in the optical industry.

Go for circular, oval or curved frames that serve as geometric contrast to the square shape of the jawline. Cat-eye sunglasses can also work, since they sit up higher on the face, which also acts to balance the bottom of the face.

Getty ImagesRound-shaped sunglasses by Balenciaga

And feel free to bling-out with sparkling embellishments at the temples, which help create the illusion of a wider top half.

Square, rectangular and otherwise boxy frames are all shapes you can do without, since they will just make your face look more square.

Here are the best frames for round heart-shaped faces:

-Round and embellished-shaped sunglasses, such asHouse of Harlow oversized round glasses.

-Round-shaped sunglasses, such as Balenciaga’s round shades.

-Vintage-looking cat-eye style sunglasses, such as Ray-Ban Vagabond frames.

Geena Davis and Queen Latifah are living embodiments of the rounded square face, which features the broad forehead and striking jawline of a square shape, with the softening of rounded edges.

While you still want to broaden the top half of the face with rounded shapes like square faces do, there’s more room to experiment with softer angles

Tory BurchRounded aviator sunglasses by Tory Burch

Try oversized glasses like aviators, but with a sleeker, more rounded shape in order to balance your features out. Other hybrid shapes like horizontally oval frames will also compliment your shape beautifully.

Stay away from extremes in either direction, like steeply circular frames or a boxy square shape.

Here are the best frames for rounded square-shaped faces:

-Rounded aviator sunglasses, like Tory Burch Rounded Aviator Sunglasses.

-Retro-style sunglasses, such as Ray-Ban’s Wayfarers.

-Oval sunglasses, like William Rast Oval Sunglasses.

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