Our research interviewers intercepted buyers and non-buyers as they exited six Luxottica stores (including Sunglasses Hut, OPSM and Laubman & Pank Optometrists chains), conducting 6000 interviews with interlocking quotas based on regions, brand, optical or sunglass purchase. Any complaints by non-buyers who requested follow-up were forwarded to head office within 24 hours.