Application of real-time iris recognition in wavefront aberration-guided LASIK with femtosecond laser flap creation

Objective To evaluate the application of real-time iris recognition in wavefront-guided laser in situ keratomileusis ( LASIK) with femtosecond laser flap creation for correction of myopic astigmatism.Methods A total of 98 patients ( 189 eyes) with myopic astigmatism were randomly divided into two groups: the experimental group ( 49 cases,95 eyes) accepted the flap created by iris recognition-combined wavefront aberration-guided LASIK with femtosecond laser,and the control group ( 49 cases,94 eyes) accepted the flap created by conventional wavefront guided LASIK with femtosecond laser.The eye cyclotorsion and pupil centroid shift in experimental group were observed during treatment.The naked visual acuity,best-corrected visual acuity, the degree and axis of astigmatism,wavefront aberration,the center of optical zone and complication were compared between two groups at 1 month,3 months and 6 months after treatment.Results In experimental group,according to the absolute value of eye cyclotorsion and pupil centroid shift,static iris recognition detection indicated that eye cycloductional misalignment was 2.03°±1.75°,pupil centroid shift was ( 0.27±0.14) mm in the X axis,and ( 0.21±0.16 ) mm in the Y axis; Dynamic iris recognition detection showed that the intraoperative cyclotorsional misalignment range was from 0 to 5.2°.Compared with the preoperative best-corrected visual acuity,the naked visual acuity of 88 eyes in experimental group and 76 eyes in control group were unchanged or improved at 6 months after operation,the difference was statistically significant ( χ 2 = 5.71,P 0.05) .The degree of astigmatism in experimental group( - 0.21±0.23) D was significantly lower than that in control group ( - 0.35±0.29) D( t = 3.68,P 0.05) .In experimental group,46 eyes became non-astigmatism at 6 months after treatment and in control group 31 eyes,there was statistical difference ( χ 2 = 4.67,P 0.05) .The center of optical zone within 0.2 mm from corneal center was 89 eyes ( 93.7%) in experimental group and 76 eyes( 80.8%)in control group,there was significant difference between two groups( χ 2 = 7.02,P 0.05) .At 6 mm pupil size,there was significant difference between third order coma aberration of experimental group and control group( t = 2.11,P 0.05 ) .Conclusion The real time iris recognition can effectively correct eye cyclotorsion and pupil centroid shift,make axial treatment and the degree of astigmatism more precise,and lower the amplification of coma aberration,improve visual quality after LASIK