| Part1Refractive Effect of Microwave ThermokeratoplastySection1Cornea Preservation by Organ Culture and Artificial Anterior Chamber MountingPurpose:To establish suitable research model for refractive effect of microwave thermokeratoplasty.Methods:All of12human corneoscleral buttons were randomly divided into2groups,6corneas each. Corneas in experimental group were preserved by organ culture for7days. The organ culture medium contained Eagle’s minimum essential medium(MEM) with additives and2%fetal bovine serum. The corneal materials were organ-cultured under37℃,5%C02,95%O2.. Before and after organ culture, the endothelial cell parameters, the cell count, size, coefficient of variation included, the central corneal thickness and the keratometry of corneal anterior and posterior surface were evaluated with specular microscope, ultrasonic, and videokeratography. The other6were treated as blank control. Both groups were stained with rhodamine-phallacidin and arcidine orange to check the morphosis of corneal endothelial cells and epithelial cells with laser scanning confocal microscope. The loss of endothelial cell was calculated. Results:Corneas of the experimental group kept transparent after organ-cultured for7days. In the experimental group, the corneal endothelial cell count was2714±372cells/mm2and2562±406cells/mm2before and after preservation respectively, the cell size:375±56μm2and399±61μm2, coefficient of variation:0.22±0.075and0.26±0.010. The loss of endothelial cell was5.60%. The central corneal thickness was538±43μm and569±31μm before and after, respectively. The keratometry readings of corneal anterior surface was47.70±2.29D and48.46±2.02D, posterior surface,-(6.76±0.70) D and-(6.80±0.45) D, before and after, respectively. All these differences were statistically significant except the difference of the corneal posterior surface keratometry readings. Comparison of morphosis of the experimental group and that of control showed no obvious difference.Conclusions:It is feasible to establish suitable model to study the refractive effect of microwave thermokeratoplasty. Section2Refractive Effect of Microwave ThermokeratoplastyPurpose:To study the parameters of microwave thermoeratoplasty and their impact on corneal refraction and dynamic changes after microwave treatment.Methods:All of the40human corneoscleral buttons were randomly divided into4groups,10each. Buttons of group A, B, C and D were treated with100W/100ms,150W/200ms,150W/500ms and150W/600ms microwave respectively. The keratometry readings were obtained with videokeratography before and7day after microwave thermokeratoplasty. And all the buttons were observed with inverted phase contrast microscope30min,1d,3d,5d and7d after microwave treatment.Results:The keratometry readings of corneal anterior surface on the7t day after microwave thermokeratoplasty were flatter than before. The change was1.25±0.72D,2.07±0.98D,5.43±1.22D and6.37±3.58D in group A, B, C and D respectively. The differences between groups were statistically significant. In group A,8out of10buttons restored their transparency on the3rd day after treatment, and all of these10buttons restored their transparency on the5th day. In group B,5out of10returned transparent on the3rd day, the rest5returned on the5th day, while in group C, none returned transparent on the3rd day,9out of10returned transparent on the5th day, the last one failed to restore its transparency. In group D, none returned transparent on the3rd day,8out of10returned transparent on the5th day, the last two failed to restore their transparency.Conclusions:The anterior corneal surface can be flattened by microwave thermokeratoplasty with power between100W and150W, and with duration between100ms and600ms. Part2Impact of Corneal Collagen Crosslinking on Cell Viability of Corneal Stromal/Endothelial Cells with Different Treatment ParametersPurpose:To find the impact of corneal collagen crosslinking on cell viability of corneal stromal/endothel ial cells in air, pure oxygen or pure nitrogen, with different concentration of riboflavin solution and with different irradiation parameters of ultraviolet light A, such as irradiances, durations and irradiation doses.Methods:Several corneal buttons were taken to do primary culture of human corneal stromal/endothelial cells. The cell viability was evaluated with MTT after treated by riboflavin solution combined with ultraviolet light A irradiation. The experiment groups were termed with treatment environment (in air, pure oxygen or pure nitrogen), riboflavin solution concentration (0.025%,10%or blank control) and irradiation parameters of ultraviolet light A (different in irradiances, durations and irradiation doses).Results:Treatment atmosphere (in air, pure oxygen or pure nitrogen) or riboflavin solution concentration (0.025%,10%or blank control) didn’t play a significant role on cell viability of corneal stromal/endothelial cells, while irradiation doses, independent of irradiances and durations, did.Conclusions:The cell viability of human corneal stromal/endothelial cells can maintain stable treated by riboflavin solution and ultraviolet light A irradiation with different atmospheres, riboflavin concentrations and irradiation doses no more than4.05mJ/cm2. |
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