Optical colonoscopy is the standard method for evaluating the colon. This technique allows evaluation of the entire colon in most patients. Full colonoscopy including examination of the cecum is associated with an increased detection rate of advanced neoplasia, as 33-50% of advanced neoplasia is located in the proximal colon. After an incomplete optical colonoscopy, participants are required to undergo another test in order to exclude clinically relevant lesions to reduce the risk of proximal cancer which has been shown to increase by twofold when colonoscopy was incomplete.