Our central hypothesis is that HRME can improve the efficiency and clinical impact of endoscopic screening and surveillance of esophageal squamous cell neoplasia by providing in-vivo optical biopsies comparable to standard histology. Specifically, HRME will allow more detailed evaluation of Lugol's abnormal areas, allowing selective biopsy or removal of neoplastic mucosa. We hypothesize that this will improve the accuracy and diagnostic yield of mucosal sampling.