By Elizabeth Snead, Los Angeles Times Staff Writer Nerdy eyeglasses are very much in vogue, as evidenced by Katie Holmes' new trend-setting black horn rims, recently seen perched on her petite nose for one of her well-paparazzied walks to work in New York. Given that Mrs. Cruise wants to be seen as a "serious" actress (she's starring on Broadway in a revival of Arthur Miller's "All My Sons" Oct. 16-Jan. 11), it's not surprising that she's adopted the instant IQ accessory. If there's one assumption made about people who wear nerdy glasses, it's that they're way brainer-than-thou. Horn rims practically scream Mensa member. (That's the organization for people with higher-than-average IQs.) Although round geek eyeglasses can also signal that you're a member of Harry Potter's fan club. Mensa or Potter, either way, you're a bigtime reader. Check out the gallery to see some stars -- Cate Blanchett, Nicole Kidman, Jennifer Garner, Chloe Sevigny, Natascha McElhone, Molly Sims, Tina Fey, Felicity Huffman, Amy Smart -- who've joined the fashionable faux Hollywood intelligentsia. Vote on who has geek chic, or who might be better off with contacts. We've also included some celebrity wiseguys -- Johnny Depp, Elvis Costello, Paul Giamatti, directors Woody Allen, Kevin Smith, Steven Spielberg and Martin Scorsese -- who made nerd eyewear their signature style. Hey, maybe these guys really are smart.