A cystoscopy is a urology procedure that allows a urologist to examine the lining of the bladder and the urethra. An instrument called a cystoscope is inserted into the urethra and guided to the bladder. The cystoscope is made up of a long, thin tube with a light and a camera at the end. This procedure is commonly used to diagnose and treat bladder conditions. It can also be used to diagnose an enlarged prostate.