Colonoscopes are categorized into proctoscopes and colonoscopes; proctoscopes can only examine the rectum, while colonoscopes can examine both the rectum and the colon. Proctoscopes and colonoscopes are divided according to their length. Proctoscopes can mainly observe the rectum, anal canal and the lower end of the sigmoid colon, and are used to visualize the area straight on to see if it is diseased. While colonoscopy is performed by inserting the lens deep into the colon, reaching the ileum and slowly backing up from the ileum under direct camera vision, passing through the ileum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anal canal, so that the examination of all the areas passed through can be covered. Regular medical checkups are recommended for the normal population, and colorectoscopy is an option to observe the presence of intestinal polyps and other conditions as prescribed by the doctor.