| Purpose:To investigate the changes in straylight values before and after FS-LASIK and analyze relevant factors underlying for the changes. To investigate the clinical outcomes of VisuMax system FS-LASIK flap measured by OCT, to assess the accuracy, repeatability, and regularity of VisuMax femtosecond laser flap.To investigate the change of flap thickness and the factors influencing flap thickness.Methods:ninety-two eyes of92patients who underwent FS-LASIK were included in this study. There were38males (38eyes),54females (54eyes), Straylight values were measured by C-Quant straylight meter preoperatively and1day,1week,1month,6month and lyear postoperatively. Sixty-eight eyes of38patients who underwent FS-LASIK were enrolled in this study and divided into2groups depending on the intended flap thicknesses (100μm and105μm), OCT was used to assess flap thicknesses1week,lmonth,6months postoperatively.The thicknesses of flap and residual bed in the seven measuring points were1mm,2mm,3mm away from center of cornea on the horizontal and the center of cornea itself.Results:1.Straylight values were (0.88±0.19),(1.07±0.21),(0.98±0.19),(0.96±0.16),(0.94±0.15)and(0.87±0.22)before and lday, lweek,lmonth,6month after FS-LASIK. Straylight values increased significantly1day,1week,lmonth after surgery(F=15.505, P=0.000), but there was no statistically significant difference between preoperative and6month or1year postoperative straylight values (t=-1.441,P=0.124;t=0.239, P=0.811).2.No correlations between age,refractive error, pupil size or central cornea thickness and straylight values observed before surgery (P>0.05). The energy was statistically significant related to the changes of straylight values1day,1week after surgery(r=0.465,0.375,0.261;P<0.05).3.Straylight values were statistically significant difference1day postoperatively between the patients had OBL and no OBL in surgery (t=-2.288,P=0.024).4.The straylight values and changes were statistically significant difference between the patients had haze and without haze1month postoperatively (t=2.199, P=0.042;t=2.339, P=0.030).5.At1weeek,1 month,6months after surgery, the thickness of flaps in1OOμm and105μm group was (107.92±5.56)μm,(108.79±4.78)μm,(106.69±5.74)μm and (109.36±6.26)μm,(112.21±4.37)μm,(108.53±7.27)μm.6.The results of accuracy in100μm and105μm groups were(F=4.995,P=0.000;F=1.918,P=0.051;F=1.806,P=0.114)and(F=1.739,P=0.213;F=1.931,P=0.049;F=1.810,P=0.083).7.Standard deviation of flap thickness in the two groups were5.56μm,4.78μm,5.74μm and6.26μm,4.37μm,7.27μm.8.The results of uniformity in100μm and105μm group were(F=5.410,P=0.000;F=8.914,P=0.000; F=3.084,P=0.052)were(F=2.000,P=0.143;F=3.431,P=0.048;F=1.786,=0.211).The results of comparison of flap thickness in differrnt zones in100μm and105μm group were (F=0.919,P=0.409;F=0.701,P=0.504; F=0.547,P=0.584)and (F=1.990,P=0.142; F=4.079,P=0.020;F=1.770,P=0.175)1week,lmonth,6months postoperatively.9.There was a correlation between uncorrected visual acuity,Q value of back surface of cornea and the thickness of corneal flap measured6months after surgery.Conclusion:1.Straylight values increased significantly after the surgery and decrease partially as time going, the values go back to preoperative level after FS-LASIK. The straylight values may be related to OBL,haze and energy.2.With the time go by,patients have stable visual acuity, VisuMax femtosecond laser flap thickness have good accuracy,repeatability,the architecture of flaps are uniform and regular. |
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