New technologies have been developed to enhance the visualization of colorectal mucosa to unmask even minute mucosal lesions and identify neoplastic lesion from non-neoplastic lesions. In particular, there appears to be strong evidence that pan-colonic chromoendoscopy enhances the detection of colorectal neoplasm in the colon and rectum. However, this technique is time-consuming because of both the dye spraying and suction of collected dye in the dependent portion, and therefore it is unsuitable for routine application. To overcome this inconvenience, optical-digital method involves conversion of the optical characteristics of the light used for illumination or imaging with a light source differing in optical characteristics from ordinary white light (WL), such as narrow band imaging (NBI), Fujinon imaging color enhancement (FICE), auto-fluorescence imaging (AFI) and infra-red imaging (IRI).