False-colour, low-power scanning electron micrograph (SEM) of the human eye, showing the ciliary body & iris. The deeply folded tissue at left & top is the ciliary body, which normally encircles & controls the lens of the eye, flattening it to focus distant objects onto the retina & making it more spherical to focus closer ones. In this view, seen from the back of the eye, the lens has been removed. As a result, one can see through to the less folded muscles of the iris, which control the aperture of the pupil (the black area at bottom right) & so the amount of light that reaches the retina. Magnification: x2.5 at 35mm size. Yellow tint. Reference: MICROCOSMOS, figure 2.9, page 19.