The practical value of first time iris recognition in wavefront aberration guided LASIK

Objective To evaluate the practical value of first-time iris recognition in wavefront aberration-guided laser in situ keratomileusis (LASIK).Methods In a randomized contrast study,101 patients (202 eyes) with myopia were randomly divided into 2 groups:the iris recognition group (50 cases,100 eyes) that agreed to undergo first-time iris recognition combined with wavefront-guided LASIK,and the non-iris recognition group (51 cases,102 eyes) that agreed to undergo conventional wavefront aberration-guided LASIK.Uncorrected visual acuity,refractive error,higher order aberrations and contrast sensitivity were compared between the two groups at 1 month,3 months and 6 months postoperatively.The data were analyzed by SPSS 17.0 statistical software,a t test for the measurement data,and a chi-square test for the enumeration data.Results Six months after the operation,the number of patients who gained more than 1 line of best spectacle-corrected visual acuity (BSCVA) in the iris recognition group (62 eyes,62.0％) was significantly more than that of the non-iris recognition group (48 eyes,47.1％) (x2=4.99,P＜0.05).The degree of astigmatism in the iris recognition group (-0.19±0.24 D) was significantly lower than that in the non-iris recognition group (-0.30±0.36 D) (t=2.49,P＜0.05).At a 6.0 mm pupil size,there was a statistically significant difference in third-order aberration root mean square value between the iris recognition group and non-iris recognition group (t=2.22,3.31,P＜0.05).Six months after the operation,the contrast sensitivity of the non-iris recognition group returned to their preoperative baseline.However,the iris recognition group had slightly better contrast sensitivity than their preoperative levels.Conclusion First-time iris recognition can increase visual quality in wavefront aberration-guided LASIK. Key words: Myopia;  Iris recognition ;  Wavefront aberration;  Keratomileusis,laser in situ