The Clinical Study Of The Changes Of Central Cornea Tissue In Vivo Confocal Microscopy After Laser In Situ Keratomileusis In Myopia

Laser in site keralomileusis (1ASIK) is a new technique for the correction of moderate to high myopic,with explosively increasing popularity worldwide. After this procedure, flatting of die central cornea! curvature due to tissue removal results in decreased refiactive power (myopic correction). LASK. offers advantages, such as minimal postoperation pain and faster clinical and functional recovery, as well as less regression and haze forrnationJiowever, biological diversity in the wound healing is thought to be a major factor limiting the predictability of the outcome of refiactive surgical procedure such as laser in site keratomileusis.Comeal wound healing is critical to the success of excimer laser ablation to optimize visual performance.Recently ,in vivo confocal microcopy has been introduced as a new tool for the evaluation of wound healing after refractive surgery in humans .It's real -time viewing of structure in living cornea at the cellular level in four dimensions (X,Y,Zand time).In addition, the confocal microscopy through focusing technique has been developed for measurement of cornea! sublayer thickness and estimation of the cornea! cell-level construction and the relation between changes of histopathology and refractive outcomes.Our study comsists three parts. The aim of first part of study (In Vivo Confocal Microscopy of Central Cornea of the myopia) is to quantify keratocyte according to stromal region and subject age and to measure the thickness of its layers of central cornea in a group of myopic human in vivo. This research also included qualitative andquantivative analysis die difference layers of comeal tissue and also the difference in anatomy and histology in persons of difference myopic conditions. A randomized, standard comparative trial was designed The study comprised 89 patients (178eyes) who diagnosed as myopia in the Eye Center of Tianjin Medicical university from 2002.8-2003.4.18 (36 eyes) emmetropia patients were selected as control group. All eyes were done in vivo a confocal microscopy to study the morphology of the keratocytes both in qualitative and quantivative analysis. The examination include the best corrected visual acuity, computer optometryand slit-lamp biomicroscopy .The results were as follows: As a whole.the thickness of the total comeal and the thickness of stromal myopic group are thinner than of normal control group.There of are no difference between two groups in epithelial thickness, density of keratocytes quantified in anterior and posterior strorna, and in endothelium cell counts .In high myopic group, the mean epithelial thickness, the total corneal thickness, stromal thickness, density of Keratocyte quantified in posterior, endothelium cell counts, polymorphology and pleomorphism were abtained. The datum is significantly different from low and moderate myopic group and statistically significant There are some differences in anatomy and physiology between normal and high myopic group. The endothelium cell counts of high myopic eyes deceased significantly and showd negative correlation with the manifest spherical equivalen .The averge size of endothelial cell increased The ploymorphism of endothelial cell showed positive correlation with the manifest spherical equivalent, and pleomorphism of endothelial cell showed no correlation with the manifest spherical equivalent Epithelial thickness showed no correlation with the manifest sphericalequivalent .the total cornea thickness and stromal thickness showed negative correlation with the manifest spherical equivalent The density of endothelial cell showed negative correlation with the manifest spherical equivalent The epithelail thickness showed no correlation with age. The density of basement-membrane cells showed negative correlation with age. The density of keratocyte quantified in anterior and posterior stroma showed negative correlation with age, and the density of endothelial cell showed negative correlation with age. The morphology of endothelial cell showed changes and the average of end...