The first step in this investigation involved setting up photographic and staining protocols for study investigators and training personnel. The five study investigators, (Carolyn Begley, OD, MS, Bloomington, IN, USA; Barbara Caffery, OD, Toronto, ON, CA, Clark Springs, MD, Indianapolis, IN, USA; Joseph Tauber, MD, Kansas City, MO, USA; and JD. Nelson, St Paul, MN, USA). chosen for their experience in grading ocular surface staining, participated in this phase of the study. Four of the sites were in private practice and one (Indiana University, Bloomington, IN, USA) was in a university setting. The Coordinating Center for the study was located at Indiana University, which also served as a clinical site. Following data collection, study investigators had access only to de-identified photographs and data.