We consider transmission through pair-correlated random distributions of lossless dielectric (globular, cylindrical, or plate-like) scatterers with length parameter a and average spacing small compared to wavelength. Each optical particle is centered in a tough adherent transparent coating whose outer surface (sphere, cylinder, or slab) has radius b ≥ a. The corresponding attenuation coefficients involve an integral of the appropriate radial-distribution function. Using the scaled-particle equations of state and statistical-mechanics theorems, we evaluate explicitly as a rational function of the volume fraction w of the fluid of rigid b particles. We obtain with β0 as the uncorrelated value; for spheres decreases more rapidly with increasing w than for cylinders, and decreases faster than , the result for slabs. We apply the results for cylinders in terms of to the problem of the transparency of the cornea (whose collagen fibers are the scatterers), as posed by Maurice. The value w ≈ 0.6 gives good accord with the essentials of the data for the transparency of the normal cornea, and the opacity that results from swelling is accounted for by corresponding smaller values of w. Thus, the normal cornea is modeled as a very densely packed two-dimensional gas, with gas-particle (mechanical) radius about 60% greater than the fiber (optical) radius.
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