AIM: To investigate the clinical effect of small incision lenticule extraction(SMILE)for super high myopia.

METHODS: Totally 64 cases(128 eyes)patients with super high myopia, were randomly divided into observation group and control group, 32 cases(64 eyes)in each group. The two groups were separately treated with SMILE or femtosecond laser LASIK(FS-LASIK). We calculated the effectiveness index and safety index by contrastive observation of clinical effects in all patients included uncorrected visual acuity, best corrected visual acuity and postoperative spherical equivalent at preoperative and postoperative 1d, 1wk, 1, 3 and 6mo.

RESULTS: The safety index: the observation group and the control group at 6mo after operation were respectively 1.10±0.10 and 1.08±0.12, the difference between the two groups was not statistically significant(P>0.05). The validity index: the observation group and the control group at 6mo after operation were respectively 1.08±0.12 and 1.06±0.14 and there was no significant difference between the two groups(P>0.05). Postoperative spherical equivalent at 6mo in the observation group was 0.09±0.36D, that in the control group was 0.36±0.46D. After 6mo, the count of spherical equivalent refraction within ±0.50D were 58 eyes(90.1%)in observation group and 49 eyes(76.6%)in the control group, within±1.0D were 64 eyes(100%)and 60 eyes(93.8%).

CONCLUSION: SMILE is safe and effective in the treatment for super high myopia. The postoperative visual acuity and diopter can be stabilized earlier by comparing with FS-LASIK.