You can swap out the removable sunglass lenses for clear versions, or throw in your prescription in daylight (tinted) or indoor flavors, since many optical stores stock appropriately sized lenses.

ENGADGET: Insert Coin: Eyez 720p video-recording glasses (video)

And the technique is fascinating: black-and-white cinematography (on color stock with the color bleached out), soft images via lenses that now qualify as antiques, performances that echo the old film-noir acting style.

WSJ: Film Review