ABSTRACT
AIM: To investigate the characteristics of changes in corneal epithelial thickness at the early postoperative stage of femtosecond assisted laser in situ keratomileusis(FS-LASIK)and its related influencing factors.METHOD: Retrospective study. A total of 120 patients(240 eyes)of myopia undergoing FS-LASIK from May 2021 to June 2022 were selected. The corneal epithelium thickness in the central area, inner ring area, and outer ring area of patients before and at 1d, 1wk, 1 and 3mo after operation was recorded. The relationship between the variation of corneal epithelium thickness and spherical equivalent, optical zone diameter, depth of cut and cutting ratio was analyzed by Pearson correlation.RESULTS: There was no statistical significance in corneal epithelial thickness in the central area, inner ring area and outer ring area at 1d after FS-LASIK compared with that before operation(P>0.05). At 1wk, 1 and 3mo after surgery, the corneal epithelial thickness in the central area, inner ring area and outer ring area increased compared with that before surgery, and the corneal epithelial thickness in the central area and inner ring area at 1 and 3mo after surgery was greater than that in the outer ring area(all P<0.05). The corneal epithelial thickness in the central, inner and outer ring areas of high myopia patients was thicker than that of low and moderate myopia patients before operation. The corneal epithelial thickness in the central, inner and outer ring areas of high myopia patients was thinner than that of low and moderate myopia patients at 1wk after operation(P<0.05). At 1 and 3mo after operation, the corneal epithelial thickness in the central, inner and outer ring areas of patients with high myopia was greater than that of patients with low and moderate myopia, and the changes of corneal epithelial thickness in the central, inner and outer ring areas were greater than those of patients with low and moderate myopia(P<0.05). The results of Pearson correlation showed that the changes in corneal epithelial thickness in the central and inner ring area were positively correlated with the corneal curvature, depth of cut and cutting ratio at 3mo after surgery, and they were in negative correlation with the age, spherical equivalent and optical zone diameter(P<0.05).CONCLUSION: The corneal epithelial thickness of patients thickened after the FS-LASIK operation, and it was correlated with age, corneal curvature, preoperative depth of cut, cutting ratio, spherical equivalent and the optic zone diameter.
ABSTRACT
@#AIM: To investigate the effect of cultured limbal stem cells on proliferating of vascular endothelial cells and validate the theory of limbal stem cells.<p>METHODS: The limbal stem cells and epithelium cells of bulbar conjunctiva were cultured and determined by immunohistochemistry staining with AE-5. The supernatant was collected and added into the cultured human umbilical vein endothelium cells(ECV-304). The negative control was set up. After 24h, MTT was done to detect endothelium cell proliferation. The statistical analysis was done by analysis of Variance.<p>RESULTS: Negative stain of AE-5 can be seen in limbal stem cells and positive stain can be seen in conjunctiva cells. The ratio of MTT added by limbal stem cell supernatant, conjunctiva epithelium cell and negative control were 2.097±0.079, 1.981±0.034 and 1.990±0.044, respectively. There were significant difference among the three groups(<i>F</i>=9.169, <i>P</i>=0.000). The proliferate activity of vascular endothelial cells added by supernatant of limbal stem cells was higher than the other two groups(<i>P</i>=0.005 and <i>P</i>=0.007, respectively).<p>CONCLUSION:The supernatant of limbal stem cells can improve the proliferation of vascular endothelium cell. This may be the unique characteristics of limbal stem cells. This study provides more evidences for the theory of limbal stem cells by determining the functional methods.