A retroview in the colon permits an 11-25% increase in the adenoma detection rate when compared with a standard straight forward view during colonoscopy. This can often be accomplished in the rectum or the proximal colon by using dial controls and shaft manipulation to turn the tip of a standard colonoscope 180°. A special slim caliber instrument, the "Third Eye Retroscope" (a backward viewing device) has been developed which is inserted through the working channel of a colonoscope. New colonoscopes are being developed that have the capability of side vision with accompanying light illumination which, with wide angle lenses, provide an almost complete retroview of the colon.