We designs and implement an instrumental methodology of analysis of the pupillary response to chromatic stimuli in order to observe the changes of pupillary area in the process of contraction and dilation in diabetic patients. Visual stimuli were used in the visible spectrum (400nm–650nm). Three different programs were used to determinate the best stimulation in order to obtain the better and contrasted pupillary response for diagnosis of the visual perception of colors. The stimulators PG0, PG12 and PG20 were designed in our laboratory. The test was carried out with 44 people, 33 men, 10 women and a boy (22–52 and 6 years), 12 with the stimulator PG0, 21 with PG12 and 17 with PG20, 7 subjects participated in more than a test. According to the plates of Ishihara, 40 of those subjects have normal vision to the colors, one subject suffers dicromasy (inability to differ or to perceive red and green) and while three of them present deficiencies to observe the blue and red spectrum (they suffer type II diabetes mellitus). With this instrumental methodology, we pretend to obtain an indication in the pupillary variability for the early diagnose of the diabetes mellitus, as well as a monitoring instrument for it. © 2004 American Institute of Physics