Any fashionista knows that no spring outfit is complete without a pair of killer shades. Sunnies (a term for sunglasses we borrowed from our friends down under) this season included the classic aviator, retro inspired cat-eyed frames, even a new twist on an old favorite with the renaissance of round frame specs a la Olsen twins.   BACK TO START   WHAT: Round tortoise shell sunnies WHERE: Forever 21 HOW MUCH: $5.80   WHAT: Carrera Champion aviators WHERE: Net-a-Porter HOW MUCH: $150   WHAT: Armani Exchange aviators WHERE: Nordstrom HOW MUCH: $70   WHAT: MICHAEL Michael Kors Cozumel WHERE: Nordstrom HOW MUCH: $95   WHAT: Jeepers Peepers flat tops WHERE: ASOS HOW MUCH: $24.62   WHAT: Marc by Marc Jacobs temple WHERE: Nordstrom HOW MUCH: $98       BACK TO START