If you enjoy a party with formal attire, you can wear contact lenses or colored contact lenses. that must make you look beautiful. If you don't want to wear contact lenses, you can wear a pair of black framed eyeglasses(if you a man) for a handsome look. If you are a women, maybe you can try this eyeglasses,http://www.firmoo.com/eyeglasses-p-1876.html. The flower design on the temple will make you look charming.
To match your formal attire, I think half-rimmed eyeglasses will be a good choice. Half-rimmed glasses make people look smarter and more delicate due to their semi rimless design, thus they can enhance your looks if you wear semi rimless glasses with your formal attire. However, choose a pair of glasses that go well with your formal attire will depends on your personal styles. You should try different styles of glasses on to determine which one will suit your formal attire best.
It is mainly to the requirements of the frame. If you engage in a work which needs to give people a solemn image, such as civil servants, salesman. You can try to choose a more traditional frame, such as the gold frame, the shape should not exaggerate, and the lens does not have a color. If you want to show your personality, such as designer, broker, make-up artist or star. You can wear the plastic frame which can show the personality, the shape can also be more exaggerate. If your work do not need to contact with others, such as programmers, you can choose your favorite glasses, but not be too different, in order to avoid being on the note of your boss.