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D.W. Hahn, K. Kim, J.V. Jester; Role of Keratocytes in Corneal Transparency as Assessed by Classical Light Scattering Theory . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2184.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Recent studies suggest that increased light scattering from corneal keratocytes contributes to the loss of corneal transparency and the development of haze, for example following excimer laser corneal ablation. Perturbations in the refractive index of keratocytes have been proposed as a possible biophysical mechanism underlying this phenomenon. To better understand the role of keratocytes in the development of corneal haze, we have modeled cells using classical light scattering theory. Methods: Keratocytes in a transparent corneal matrix were modeled using two classical light scattering theories, namely the solution for homogenous spheres of arbitrary size, and the solution for arbitrarily–sized coated spheres such that the core material and outer shell may have different optical properties. A parametric study was performed to assess the degree to which differential scattering cross–sections were altered when the refractive indices of the various components were perturbed. Baseline calculations were matched to properties anticipated for normal corneal structures. Results: The calculated scattering coefficients for small angle (forward) scattering were found to vary significantly for modest changes in the refractive index. For coated spheres, changes of only 10% in the refractive index of a 200–nm thick outer shell increased the forward scattering by more than an order of magnitude. Similar effects were observed for changes in the refractive index of the solid sphere. In addition, resonance behavior was observed at select forward scattering angles, resulting in 100–fold enhancements of light scattering. Conclusions: The present analyses reveal that modest changes in the optical properties of corneal keratocytes can significantly alter the scattering characteristics. In particular, changes in only the outer thin shell, representing the cell wall, may induce these changes. Overall, these results support the hypothesis that small changes in the refractive index of keratocytes may underlie the development of corneal haze after injury.
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