AIM:To evaluate the influence on corneal biomechanics after small incision lenticule extraction(SMILE)and Femto LDV laser flapping in laser in situ keratomileusis(FS-LASIK).

METHODS: Preoperatively, 1mo after surgery, 101 patients(202 eyes)with myopia in each group respectively by SMILE and FS-LASIK were examined by ocular response analyzer(ORA). Parameters were compared between postoperative(1mo)and preoperative. Comparisons included the corneal thickness and corneal compensated intraocular pressure(Iopcc), Goldmann correlated IOP value(Iopg), corneal resistance factor(CRF), corneal hysteresis(CH).

RESULTS: SMILE group: IOPcc, IOPg(1mo postoperatively, 13.84±2.22,10.81±2.52mmHg)significantly changed comparing with preoperative(16.15±2.90, 15.95±3.08mmHg; t=-13.58, -32.91; both P<0.01). CRF and CH(1mo postoperatively, 7.52±1.41, 8.66±1.19mmHg)significantly changed comparing with preoperative(10.72±1.61, 10.60±1.43; t=-41.21, -24.03; both P<0.01). The difference were 3.19±1.10, 1.93±1.14mmHg respectively. FS-LASIK group: Iopcc and Iopg(1mo postoperatively, 13.99±2.33, 10.10±2.55mmHg)significantly changed comparing with preoperative(15.88±3.29, 14.86±3.34mmHg; t=-10.09、-23.00; both P<0.01). CRF, CH(1mo postoperaturely, 6.68±1.14, 7.90±1.27mmHg)significantly changed comparing with preoperative(9.93±1.85, 9.98±1.60mmHg; t=-24.84, -18.90; both P<0.01). The difference were 3.25±1.86, 2.08±1.57mmHg respectively. Changes of CRF and CH were significantly different between two groups(t=-0.351, -1.081; both P<0.01).

CONCLUSION: The postoperative corneal biomechanics and IOP measurements are lower than preoperative. SMILE are lower than FS-lasik in changes of CRF, CH.