AIM: To study the femtosecond small incision lenticule extraction(SMILE)intraoperative appear opaque bubble layer(OBL)group and the control group visual quality whether there are differences.

METHODS: A prospective cohort study were enrolled from Jun. to Sep.2015 in 116 cases of refractive surgery center of PLA included 116 eye hospital for SMILE patients. Intraoperative OBL were divided into OBL group(51 eyes)and control group(65 eyes). The best corrected visual acuity on the follow-up of OBL group and control group before and after operation on 1,3 and 6mo after the operation best corrected visual acuity(BCVA), modulation transfer function cut off frequency(MTF_cutoff), Strehl ratio(SR), objective scattering index(OSI)and total higher-order aberrations(RMSH), vertical coma(C7), horizontal coma(C8)and spherical aberration(C12)differences in visual quality index.

RESULTS:Fixed in the preoperative and postoperative each time point to compare the differences of BCVA between OBL group and control group were not statistically significant(P>0.05), OBL group and control group of BCVA in each time point comparison between 3mo and 6mo respectively compared with the preoperative difference was statistically significant(P<0.05), the two groups BCVA after 3mo and 6mo were significantly better than preoperative. OBL group and control group in SR, MTF_cutoff, OSI, C7, C12, RMSH were statistically significant different at each time point 6 index(P<0.05), and C8 had no statistical difference at each time(P>0.05). There was statistical significance of RMSH index in 1mo after operation in OBL group and control group(P<0.05).

CONCLUSION: There is no significant effect on the quality of recovery after surgery, and the effect of OBL on the visual quality of patients during the SMILE operation is small.