Comparative Study Of Visual Quality After LASIK Flap Creation With A Femtosecond Laser And A Mechanical Microkeratome

Purpose: To evaluate the clinical results of different creation way of flap by comparing studyof visual quality after LASIK flap creation with a femtosecond laser and a mechanicalmicrokeratome.Methods: Mechanical microkeratome flap group:A total of45patients90eyes were dividedinto mild myopia group15patients30eyes; moderate myopia group17patients34eyes; highmyopia group13patients26eyes; femtosecond laser flap group:A total of45patients90eyeswere divided into mild myopia group14patients28eyes;moderate myopia group18patients36eyes; high myopia group13patients26eyes. Visual acuity, contrast sensitivity, higher-orderaberrations,and the value of subjective visual quality survey were compared in the two groupsbefore and1month and3months after surgery.Result:(1)There was no statistically significant difference in visual acuity between2groups.(2)Without glare state, in mild myopia group,there was no statistically significant difference at1month and3months postoperatively between2groups in all spatial frequency of contrastsensitivity. In moderate myopia group,there was statistically significant difference at1monthand3months postoperatively between2groups in6c/d and12c/d spatial frequency of contrastsensitivity. In high myopia group,there was statistically significant difference at1month and3months postoperatively between2groups in6c/d,12c/d and18c/d spatial frequency of contrastsensitivity. With glare state, in mild,moderate and high myopia groupthere was no statisticallysignificant difference at1month and3months postoperatively between2groups in all spatialfrequency of contrast sensitivity.(3)In mechanical microkeratome flap group, the total higherorder aberration,spherical aberration and coma aberration at1month postoperatively and thetotal higher order aberration and coma aberration at3months postoperatively were higher thanfemtosecond laser flap group.In mild myopia group,the total higher order aberration and comaaberration at3months postoperatively in mechanical microkeratome flap group were higherthan femtosecond laser flap group.In moderate myopia group,the total higher order aberrationat1month postoperatively in mechanical microkeratome flap group were higher thanfemtosecond laser flap group.In high myopia group,tthe total higher order aberration,sphericalaberration and coma aberration at1month postoperatively and the total higher order aberrationand coma aberration at3months postoperatively in mechanical microkeratome flap group were higher than femtosecond laser flap group.In the high myopia group,the differences of higherorder aberration was larger than the mild myopia group and the moderate myopia group.(4)Therelationship between the change of contrast sensitivity,the total higher order aberration andcoma aberration was a negative correlation.(5)There were no statistically significant differencesin the value of subjective visual quality survey in mild,moderate and high myopia groupbetween2groups at3months postoperatively.Conclusion：（1）The femtosecond laser flap group has significant superiority over mechanicalmicrokeratome flap group in objective visual quality indicators, except for less degree of higherorder aberration, and more contrast sensitivity value.But there was no statistically significantdifference in the value of subjective visual quality survey between2groups.(2)It is necessaryto research and develop more comprehensive, more targeted visual quality questionnaire forLASIK postoperatively.(3)The accuracy and controllability of flap technology can significantlyimprove the visual quality of LASIK postoperative,and it is the direction of developmen forflap technology in the future.