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C. Martinez–Garcia, S. Mar–Saldaña, J.T. Blanco–Mezquita, R.M. Torres, J.M. Merayo–Lloves; Transmittance and scattering during wound healing after refractive surgery: Role of Myofibroblast . Invest. Ophthalmol. Vis. Sci. 2004;45(13):156.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) are frequent techniques performed to correct myopia. Both methods have been compared in their way of healing but there is not comparison about transmittance and light scattering during this process. By the scattering of light we mean the removal of energy from an incident wave Scattering in corneal wound healing is due to three parameters: cellular size and density, and the size of scar. Increase in the scattering angular width implies a decrease the contrast sensitivity. During wound healing keratocytes activation is induced and these cells become into fibroblasts and myofibroblasts. The goal of this study was to compare transmittance and light scattering in corneas operated by both techniques. We are interested in demonstrate that myofibroblasts are involved in this process by a scattering medium. Methods:Hens were operated using PRK and LASIK techniques. Animals used in this experiment were sacrificed, and immediately their corneas were removed and placed carefully into a cornea camera support. All optical measurements have been done with a scatterometer constructed in the Optics Department (University of Valladolid. Spain). This device has worked with three wavelengths comes from three lasers. Then corneas were fixed for both, light and electron microscopy analysis.Light microscopy: H&E staining was made and immunohistochemistry with anti–α–SMA antibody followed by anti–mouse IgG Texas red conjugated, nuclei were stained by DAPI. Electron microscopy. Results:Light microscopy showed a different size of scar, bigger in PRK than LASIK, with similar density of cells. That is correlated with the transmittance, lesser than 50% in PRK operated corneas and bigger than 60% in LASIK operated corneas. Immunohistochemistry showed that a lot of cells in the PRK scar are α–SM positive. Scattering measurements are correlated with the transmittance, the smaller transmittance is the bigger scattering is. In this case bigger scattering correspond with PRK corneas. The angular distribution of scattered light in PRK corneas is reproduced with a simple model, MIE model using as a data of spheres a distribution of myofibroblasts diameters. To obtain this data we used electron–microscopy photographs. Conclusions: We can conclude that LASIK corneas have better tansmittance during wound healing than PRK corneas. They have higher sensitivity of contrast because they show a lower angular width of scattering
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