Article (and answers) from Plastic and Reconstructive Surgery

The Twins Days Festival is an annual gathering of twins and multiples in Twinsburg, Ohio. The Department of Plastic Surgery at Case Western Reserve University obtained comprehensive medical and lifestyle histories of twins by means of questionnaire at the festival between 2007 and 2010. Professional photographers took standardized digital photographs of the participants in outdoor booths with overhead shades

Photographs were size-matched using Mirror software (Canfield Scientific, Inc., Fairfield, N.J.). A panel of three blinded judges (H.C.O., B.A., and K.K.) was trained to evaluate wrinkles using the Lemperle Assessment Scale. Frontal views of each twin set were arranged side by side and randomized by a nonjudge (K.V.) so that the smoker or smoker of longer duration appeared sometimes on the left side and other times on the right.