"nColor -blindness is the inability to perceive differences between some color that other people can distinguish. Using a literature search , the results indicate the prevalence of color vision deficiency in the medical profession and its on medical skills. Medical laboratory technicians and technologists employees should also screen for color blindness. This research aimed to study color blindness prevalence among Hospitals' Clinical Laboratories' Employees and Students in Tehran University of Medical Sciences (TUMS). A cross- sectional descriptive and analytical study was conducted among 633 TUMS Clinical Laboratory Sciences' Students and Hospitals' Clinical Laboratories' Employees to detect color - blindness...