A method for diagnosing a condition of a patient includes providing a color reference member that includes one reference color thereon. An electronic visual image is obtained of a patient tissue and the at least one reference color on the image. The electronic visual image is processed with the computer by analyzing the colors in the image of the patient tissue and the reference color. This analysis is performed to obtain a standardized color value of the patient tissue. A condition of the patient is diagnosed by using the standardized color value of the patient tissue so obtained.