Methods Patients with typical GERD symptoms and healthy control without GERD symptoms were included and 2 validated GERD questionnaires were completed. The endoscopist was blinded to the presence of reflux symptoms and distal esophagus was examined using standard white light endoscopy followed by i-scan. Mucosal morphology at squamocolumnar junction (SCJ) observed by i-scan were compared between GERD patients and controls.