Fig. 1. Iris topography. A. Horizontal section through the human eye. B. Cross-sections of monkey iris in miosis (1), in moderate mydriasis (2), and in extreme mydriasis (3). C.Sagittal cross-section of human iris in mid-dilation. (B, camera obscura outlines of photomicrographs from van Alphen GWHM: The structural changes in miosis and mydriasis of the monkey eye. Arch Ophthalmol 69:802, 1963)