We performed a series of studies with specialized anatomopathologists of corpse eyes with different degrees of pigmentation. The main conclusions we reached were the following (Figures 1, 2 & 3):

Figure 1: Histological simple of a low pigmented iris. Eumelanin (dark pigment) is highly concentrated and at the thick posterior epithelium, while a very thin layer is showed at the surface (anterior epithelium). In the middle, large stroma has few scattered granules of melanin.

Figure 2: Every eye, even blue ones, show a thick and dark posterior epithelium layer for light protection. Stroma contains many functional structures such as blood vessels, muscles (pupil sphincter and dilator) and collagen fi bers.

Figure 3: Typical level 4 pigmented eye showing a dark posterior and anterior epithelium, and also a high density of stroma melanin granules.