Analysis The Changes Of Postoperative Intraocular Pressure And The Relative Factors After Small Incision Lenticule Extraction

Objective: To analyze the changes of intraocular pressure(IOP)values measured by noncontact tonometer(NCT)after small incision lenticule extraction(SMILE),explore the correlations and regression equation among IOP values,central corneal thickness(CCT)and corneal curvature after procedure SMILE.Methods: 130 cases(259 eyes)received SMILE in our hospital during Feb.2016 to Nov.2016 were involved.Then 259 eyes were divided into three groups according to the spherical equivalent(SE).108 high myopia eyes in group A(SE≥-6.00D),110 moderate myopia eyes in group B(-3.00D~-6.00D)and 41 low myopia eyes in group C(SE(27)-3.00D).Three groups were all received common examination before sugery and operated with SMILE.Same glucocorticoid eye drops were given after surgery.Then record the follow-up data for 3 months,including IOP values measured by NCT,CCT and corneal curvature,and these data were analyzed by statistical software of SPSS 18.0.The ANOVA,LSD-t test were used to analyze difference of IOP before and after SMILE.The Pearson correlation was used to evaluate the relationship between IOP,IOP varies values(ΔNCT)and its influence factors.The regression analysis of IOP,ΔNCT and the influencing factors was performed with the multiple linear regression model analysis.Results:(1)ANOVA showed that there was significant statistical difference in IOP values(NCT)before and after procedure SMILE in three groups(F=147.264,143.004,72.865,P(27)0.001),as well as the LSD-t test showed.And the IOP values decreased after SMILE.The IOP values at every step of follow-up after surgery were no statistical difference(P(29)0.05).(2)The IOP values were positive correlated with CCT and corneal curvature after surgery in three groups,respectively.In group A,r=0.4356,0.295(P(27)0.05),the correlation equation between IOP and CCT,corneal curvature was Y=0.0327X-2.739(X was CCT,Y was IOP),R2=0.2057;Y=0.4748X-7.163(X was corneal curvature,Y was IOP),R2=0.08703,respectively.In group B,r=0.2807,0.264(P(27)0.05),the correlation equation between IOP and CCT,corneal curvature was Y=0.0295X-1.832(X was CCT,Y was IOP),R2=0.0788;Y=0.3837X-4.199(X was corneal curvature,Y was IOP),R2=0.06971,respectively.In group C,r=0.4101,0.6346(P(27)0.05),the correlation equation between IOP and CCT,corneal curvature respectively was Y=0.04658X-8.75(X was CCT,Y was IOP),R2=0.1682;Y=1.257X-35.92(X was corneal curvature,Y was IOP),R2=0.4027,respectively.The ΔNCT showed no correlation with ΔCCT in three groups(r=0.1269,0.1606,0.1955,P(29)0.05).And the ΔNCT showed zero correlation with the decreased value of corneal curvature in three groups(r=0.1397,0.03972,0.04514,P(29)0.05).(3)The multiple linear regression model analysis revealed that the regrssion equation of IOP values,ΔNCT and influencing factors was Y=-12.963+0.029X1+0.31X2(Y was IOP,X1 was CCT,X2 was corneal curvature);Y=2.276+0.032X1+0.108X2(Y was ΔNCT,X1 was ΔCCT,X2 was the corneal curvature variation),the regression equation all had statistical significance(F=29.05,19.394,P(27)0.001).Conclusion:(1)The postoperative IOP values measured by NCT is lower than preoperative of SMILE,and there was no significant influence to use glucocorticoid eye drops in short terms.(2)There were positive correlation between postoperative IOP values and CCT,corneal curvature variations after procedure SMILE.And the ΔCCT and corneal curvature variations influenceΔNCT toghter.