| OBJECTIVE To evaluate early-stage visual outcome and corneal high-order abbreviations after Small-incision lenticule extraction(SMILE)for correction of myopia,and to investigate the influence of potential related factors on these outcomes.METHOD A consecutive case study.398 eyes of 200 patients who underwent SMILE to correct myopia as well as 182 eyes of 92 patients after femtosecond laser-assisted LASIK(FS-LASIK)at Eye Center of Peking Union Medical College Hospital from January 2016 to January 2017 were included.Comprehensive ocular examinations including uncorrected distance visual acuity(UCVA)/best corrected visual acuity(BCVA),corneal topography,intraocular pressure,central corneal thickness(CCT),refractive evaluation,slit-lamp microscope and fundus examination were carried out before surgery.Patients in both groups were followed up on day 1,day 10,1st month and 3rd month after surgery and UCVA,BCVA,refractive outcome at each time point were compared with repeated measures ANOVA,independent t-test and chi-square test.The correlation between UCVA early after SMILE and potential influential factors such as age,spherical or cylindrical diopters,etc,were analyzed with Pearson or Spearman test.Central corneal thickness was re-evaluated for 72 eyes of 36 patients to compare the practical value with corresponding theoretical value with paired t-test.Besides,Total HOA and 3rd to 5th stage HOA were evaluated on 59 eyes of 30 patients before and 1 month after SMILE and the preoperative and postoperative outcomes were compared with paired t-test.Also,correlation between postoperative HOA and potential influential factors were analyzed.RESULT no significant difference was found in age,gender,spherical equivalent(SE),or CCT between SMILE and FS-LASIK groups.Repeated measurement ANOVA found significant difference in UCVA at each follow-up time between the two groups(F=17.73,p<0.001).Especially,UCVA on 1st day after FS-LASIK was significantly better than that of SMILE,While on 10th day and 1st month,UCVA of SMILE group was signifcantly better than that of FS-LASIK group.As for the proportion of eyes whose UCVA was no less than 20/20,SMILE group got a smaller proportion on the 1st day while a bigger proportion on the 10th day compared with FS-LASIK group.But after 1 month,the difference between the two surgical groups disappeared.A negative correlation between spherical diopter and early-stage logMAR UCVA was observed,with coefficient of-0.135 and-0.179 on day I and day 10,respectively.Age,cylindrical diopter,CCT,size of incision didn’ t show correlation with visual outcome after SMILE.Total HOA,together with coma,spherical abbreviation,secondary astigmatism,secondary coma and secondary trefoil increased significantly 1 month after SMILE.Spherical diopter showed positive correlations with total HOA and secondary astigmatism while cylindrical diopter was negatively correlated with secondary astigmatism.Residual stromal thickness was positively correlated with coma while ablation ration show negative correlation with postoperative total HOA as well as secondary astigmatism.CONCLUSION Visual recovery after SMILE was slower than FS-LASIK at an early stage,especially on the 1st day.After 1 month,there was no significant difference in visual outcome between two suegeries.1st day and 10th day postoperative logMAR UCVA of SMILE were negatively correlated with preoperative spherical diopter.Total HOA,coma,spherical abbreviation,secondary astigmatism,secondary coma and secondary trefoil increased significantly 1 month after SMILE. |
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