Calculated light transmission in the rabbit cornea as a function of wavelength for the collagen fibril distributions represented in Fig. 12a (grey curve) and Fig. 12b (black curve). Both curves were calculated using the direct summation of fields method (Freund et al., 1986), using other parameters taken from rabbit cornea (corneal thickness 360 microns, refractive index of collagen 1.355, refractive index of ground substance 1.420, collagen radius 19.4 nm, fibril density 220 fibrils per square micron).