The Effect Of Mitomycin C On Corneal Endothelial Cell Morphology In Laser Epithelial Keratomileusis

Objective: To investigate the effect of mitomycin C on corneal endothelialcell in laser epithelial keratomileusis， and the relationship with the residualcorneal stromal thickness and the application time of mitomycin C,and toanalyze the safety of the mitomycin C.Method:49patients (98eyes) treated with LASEK were observed.Afterthe ablation intraoperation,sponge of0.02%MMC was covered in the center ofresidual corneal stromal bed for some time which was related with thepre-correction degree.The first grouping: all were divided into three groupsaccording to the residual corneal stromal thickness after knowing the degree ofpre-correction:groupA:300μm≤d<320μm(11eyes),groupB:320μm≤d<340μm(10eyes)，group C：d≥340μm(77eyes); the second grouping: all were divided intotwo groups(T1&T2) according to application time of mitomycin C:group T1：15s≤t≤45s (65eyes)，group T2：45s<t≤70s(33eyes). Then measured cell density、percentage of hexagonal endothelium、 coefficient of variation、 average cellarea、 standard deviation、 maximum cell area、 minimum cell area beforeoperation and at the first weeks、 first months、3rd months and6th months afteroperation,then analyzed the changes of the parameters of the corneal endothelialcell using SPSS statistical software.Result:1. There was no significant difference in terms of the cell density、percentage of hexagonal endothelium、 coefficient of variation、 average cellarea、standard deviation、maximum cell area、minimum cell area when they were compared in its own grouping（P>0.05）.At the same time,every parameter of thecentral and peripheral corneal had no significant difference（P>0.05）.2. In the first grouping，compared the corneal endothelial cell parameters atdifferent times postoperative with that preoperative in every group：1) The corneal endothelial cell density、standard deviation、maximum cellarea、 minimum cell area had no significant difference as compared withpreoperation（P>0.05）.2) The central corneal endothelial cell variation coefficient of group B hadsome significant difference at first month postoperatively （P<0.05）,othercomparations had no significant difference（P>0.05）.3)The percentage of hexagonal endothelium of the central cornealendothelial cells in group A,B,C had some significant difference（P<0.05）at firstweek postoperatively, the others had no significant difference（P>0.05）.4) The average cell area of the peripheral corneal endothelial cells in groupA,B,C had significant difference(P<0.05） at first week postoperatively, and theothers had no significant difference（P>0.05）.3. In the second grouping，compared the corneal endothelial cell parametersat different times postoperative with that preoperative in every group:1) The corneal endothelium cell density、standard deviation、maximum cellarea、 minimum cell area had no significant difference（P>0.05）;2)The variation coefficient of central corneal endothelial in group T1andT2were smaller at first week postperatively,and the difference wassignificant(P<0.05),other comparations had no significant difference（P>0.05）.3)The percentage of hexagonal endothelium of the central cornealendothelial cells in groupT1and T2had significant difference(P<0.05)at firstweek postperatively,the others had no significant difference（P>0.05）; 4) The average cell area of the peripheral corneal endothelial cells in groupT1and T2had significant difference（P<0.05） at first week postperatively, andthe others had no significant difference（P>0.05）.Conclusion:1.In laser epithelial keratomileusis,the application ofmitomtcin C with reasonable concentration and time, did not cause any changeof corneal endothelium cell density,but caused a reduction of the percentage ofhexagonal cells, an increase of the coefficient of variation in the central cornealendothelial cells,and an increase of the average area of the peripheral cornealendothelial cells,which were transient and short-term, then all returned to thepreoperative level soon after.2.Corneal endothelial cell count should be classified as one of theexamination before LASEK as to assess the corneal status more sensitive andaccurate.