Changes In Corneal Biomechanics In Patients With Different Curvatures Myopia After SMILE

Objective: To study the biomechanical changes of femtosecond laser small incision lenticule extraction(SMILE)for myopia patients with different corneal curvatures,to observe the safety and effectiveness of the treatment,and to analyze and explore the postoperative changes of corneal biomechanical stability in patients with different curvatures.Methods: In this study,a prospective,non-randomized research method was used to select 112 right eyes of 112 myopia patients who underwent SMILE surgery.Comprehensive evaluation and follow-up of the safety and effectiveness of all patients after surgery,observing the corneal recovery and related complications;recording the naked vision of all patients according to the preoperative and postoperative time periods(1 week,1 month,3 months)(UCVA),intraocular pressure(IOPg),compensatory intraocular pressure(IOPcc)changes.The differences in corneal biomechanics of patients with different curvatures were evaluated in groups.The preoperative corneal curvature of the patients became the basis for grouping.The three groups were divided into low curvature group(<42 D,22 eyes),medium curvature group(42～45 D,79 eyes)and high curvature group(> 45 D,11 eyes).The specific comparison is divided into corneal hysteresis(CH),corneal resistance factor(CRF),central corneal thickness(CCT),UCVA,IOPg,IOPcc of each group before operation,1 wk,1 mo and 3 mo after surgery.Changes in parameters.SPSS 26.0 statistical software is used for data analysis,and the difference is statistically significant with P<0.05.Results: 1.Overall safety observation All patients SMILE surgery progressed smoothly.During the 3-month follow-up,there were no related serious complications and vision loss,indicating that SMILE surgery has a higher treatment for myopia patients with different corneal curvatures.Effectiveness and safety.2.From the data of UCVA,the condition of patients after the operation is significantly improved than before the operation,whether it is 1 wk,1 mo or 3 mo after the surgery,and the difference was statistically significant(P<0.05);indicating that each time point of postoperative follow-up Compared with the preoperative vision,the vision has been significantly improved,and it tends to be stable in various time periods after the operation.IOPcc and IOPg were reduced at 1 week,1 month,and 3 months after surgery compared with preoperatively,and the difference was statistically significant(P<0.05).The IOPcc and IOPg tended to be followed up for 1 month and 3 months after surgery.When it is stable,the intraocular pressure values in each time period are within the normal range.3.Comparison of biomechanical parameters of the three groups of patients at different times after surgery: Compare the three sets of data of corneal hysteresis(CH)at 1 week,1 month and 3 months after surgery,and the CH value decreased,and there was no statistical difference.It is worth noting that the CH value change at 1 month and 3 months in the low curvature group was smaller than the medium and the high curvature group,and the difference was statistically significant.For the middle curvature group and the high curvature group,there is no difference in CH value changes;the three groups were postoperative.In the comparison of corneal resistance factor(CRF)data before and after surgery,the CRF value was reduced and the difference was statistically significant.At the same time,the CRF changes at 1 month and 3 months after the operation in the low curvature group were all smaller than the CRF changes in the middle curvature group(the divergence was statistically significant)and in the high curvature group(the divergence is statistically significant),there is no significant difference in the changes between the middle and the high curvature group;comparison of the central corneal thickness(CCT)before surgery in the three groups,the CCT value has decreased,and the difference was not statistically significant.The changes in CCT at each postoperative time in the low curvature group were smaller than those in the high curvature group(the difference was statistically significant),the medium curvature group and the high curvature group For the data of UCVA,it did not show a big difference;at the same time,for different curvature groups,there was no statistical divergence in the changes in the value of UCVA between preoperative and postoperative follow-up,high curvature group,medium and low curvature group;IOPg,IOPcc preoperative,there was no statistically significant difference in the change value of 3 months after the operation in the low curvature group,medium curvature group,and high curvature group.Conclusions: Myopia patients with different curvatures will reduce the biomechanics of the cornea after SMILE,and the corneal biomechanics of the high curvature group and the lower curvature group will decrease more.However,the corneal biomechanics of different curvature groups tended to be stable with the increase of time.