Impact of ablation ratio on 5-year postoperative posterior corneal stability after refractive surgery: SMILE and FS-LASIK

Table 1 Patient characteristics

	SMILE group	FS-LASIK group	P value
Pre-operative data
Patient number	43	32	N/A
Study eye number	80 (38 left, 42 right)	63 (32 left, 31 right)	N/A
Sex (Male/Female) ^c	14/29	5/27	0.1
Age (years) ^b	30 (25 ~ 32)	27 (23 ~ 32)	0.13
Spherical refractive error (D) ^a	−5.98 ± 1.52	−7.70 ± 2.28	< 0.01
Cylindrical refractive error (D) ^b	−0.50 (−1.00 ~ −0.25)	−1.00 (−1.50 ~ −0.75)	< 0.001
Spherical equivalent (D) ^a	−6.33 ± 1.56	−8.26 ± 2.39	< 0.001
CDVA (logMAR) ^a	−0.03 ± 0.05	−0.02 ± 0.04	< 0.01
Axial length (mm) ^b	26.05 (25.48 ~ 26.76)	26.24 (25.50 ~ 27.25)	0.38
Central corneal thickness (μm) ^b	561 (527 ~ 573)	545 (526 ~ 568)	0.28
Intra-operative data
Cap/Flap diameter (mm)	7.5	8	N/A
Cap/Flap thickness (μm)	100–110	100	N/A
Lenticule thickness (SMILE, μm) or Ablation depth (FS-LASIK, μm) ^b	132 (104 ~ 144)	142 (128 ~ 158)	< 0.001

N/A= not applicable; CDVA=corrected distance visual acuity; logMAR=logarithm of the minimal angle of resolution; UDVA=uncorrected distance visual acuity; D=diopter; SMILE=small incision lenticule extraction; FS-LASIK=femtosecond laser-assisted in situ keratomileusis. Data are mean ± standard deviation or median and interquartile range for data that were normally or non-normally distributed. P values less than 0.05 were considered statistically significant.
^a Student’s t-test
^b Wilcoxon rank-sum test
^c Chi-squared test

ISSN: 2326-0254