AIM: To analyze the correlation of changes in non-contact intraocular pressure(IOP_NCT)and the surgical parameters after femtosecond laser small incision lenticule extraction(SMILE)for high myopia.

MOTHODS:A retrospective analysis, the clinical data of 98 patients(196 eyes)with high myopia were operated SMILE in the optometric center of Gansu Provincial Hospital from January 2018 to July 2019 were analyzed. The change of IOP_NCT before and after operation was observed, and recorded the optical zone(OZ), lenticule thickness(LT), cap thickness(CT)and residual stromal thickness(RST)and the correlation with the change value of IOP_NCT(△IOP_NCT, △IOP_NCT=IOP_preoperative-IOP _{postoperative at 6mo}).

RESULTS:After operation at 1d, 1wk, 1,3 and 6mo, the group of patients with IOP_NCT(10.84±2.14,11.00±2.19,10.65±2.43,10.45±2.04,10.61±1.39mmHg)and the preoperative(16.79±1.65mmHg)comparison have a difference(P<0.001).The optical zone and lenticule thickness were positively correlated with △IOP_NCT respectively(r=0.1537, 0.8161, all P<0.05). The cap thickness and residual stromal thickness were negatively correlated with △IOP_NCT respectively(r=-0.8362, -0.3351, all P<0.0001). Introduce the above related factors into a multiple linear regression analysis model. The regression coefficients of variables are statistical significane. The regression equation was Y=16.189+0.227X₁+0.032X₂-0.083X₃-0.007X₄(Y=△IOP_NCT, X₁=OZ, X₂=LT, X₃=CT, X₄=RST). The equation was statistically significant(F=195.704, P<0.001), and the regression model coefficient of determination R²=0.901.

CONCLUSION:The intraocular pressure changes after SMILE with high myopic were correlated with optical zone, lenticule thickness, cap thickness and residual stromal thickness. The regression equation would provide reference to evaluation the real intraocular pressure after SMILE in clinic.