Evaluation of femtosecond laser in flap and cap creation in corneal refractive surgery for myopia: a 3-year follow-up

Figures & data

Table 1 Preoperative selected characteristics

Variable	LASIK group	FS-LASIK group	SMILE group	P-value
Age (years)	23.84±4.75	23.84±4.75	24.43±5.91	0.520
Gender (M/F)	12/18	14/24	14/21	–
SE (D)	−7.49±2.05	−7.14±1.97	−8.05±2.06	0.161
CCT (μm)	582.84±12.25	578.96±12.06	579.32±10.65	0.342
Mean K (D)	43.16±1.27	43.41±1.08	43.57±1.15	0.366
CH (mmHg)	10.62±0.53	10.71±0.47	10.58±0.39	0.473
CRF (mmHg)	10.19±0.12	10.22±0.10	10.21±0.09	0.489
OSDI	11.43±10.11	11.89±9.82	11.96±9.28	0.935
TBUT	10.11±1.41	9.87±1.28	9.93±1.35	0.571

Note: Data are mean ± SD of 103 eyes of 103 patients.

Abbreviations: LASIK, laser in situ keratomileusis; FS-LASIK, femtosecond laser-LASIK; SMILE, small incision lenticule extraction; SE, spherical equivalent; CCT, central corneal thickness; K, keratometric reading; CH, corneal hysteresis; CRF, corneal resistance factor; OSDI, ocular surface disease index; TBUT, tear breakup time; M, male; F, female.

Table 2 Preoperative and postoperative data

Variable	LASIK group (30 eyes)	FS-LASIK group (38 eyes)	SMILE group (35 eyes)
Deviation of central flap or cap thickness from intended (μm)
1 month postoperative	23.37±4.41	5.03±2.49*	5.89±2.22*
3 months postoperative	23.41±4.64	5.13±3.12*	6.07±2.88*
6 months postoperative	23.39±5.43	5.08±2.39*	5.96±2.31*
12 months postoperative	23.36±4.22	5.11±2.32*	5.88±2.29*
24 months postoperative	23.36±4.20	5.02±2.41*	5.83±2.31*
36 months postoperative	23.37±4.26	5.03±2.44*	5.82±2.33*
CH (mmHg)
Preoperative	10.82±0.53	10.71±0.47	10.58±0.39
1 month postoperative	7.51±0.73‡	7.66±0.64‡	8.43±0.32‡,*,**
3 months postoperative	7.50±0.60‡	7.63±0.58‡	8.41±0.41‡,*,**
6 months postoperative	7.47±0.54‡	7.58±0.60‡	8.40±0.37‡,*,**
12 months postoperative	7.45±0.65‡	7.56±0.44‡	8.37±0.40‡,*,**
24 months postoperative	7.55±0.63‡	7.59±0.51‡	8.44±0.47‡,*,**
36 months postoperative	7.58±0.71‡	7.60±0.61‡	8.51±0.51‡,*,**
CRF (mmHg)
Preoperative	10.19±0.22	10.22±0.20	10.21±0.19
1 month postoperative	7.15±0.50‡	7.24±0.73‡	8.35±0.41‡,*,**
3 months postoperative	7.13±0.44‡	7.22±0.81‡	8.32±0.56‡,*,**
6 months postoperative	7.12±0.76‡	7.21±0.65‡	8.30±0.48‡,*,**
12 months postoperative	7.11±0.57‡	7.18±0.59‡	8.29±0.32‡,*,**
24 months postoperative	7.18±0.54‡	7.26±0.71‡	8.35±0.42‡,*,**
36 months postoperative	7.17±0.68‡	7.25±0.69‡	8.38±0.59‡,*,**
OSDI
Preoperative	11.43±10.11	11.89±9.82	11.96±9.28
1 month postoperative	18.51±14.73‡	18.29±15.24‡	18.12±13.88‡
3 months postoperative	16.42±12.09‡	15.95±11.83‡	12.03±9.87*,**
6 months postoperative	12.27±10.85	12.05±11.43	11.51±10.15
12 months postoperative	11.71±10.43	11.86±10.92	11.13±10.02
24 months postoperative	11.53±9.54	11.88±10.06	11.27±9.06
36 months postoperative	11.49±9.97	11.85±10.02	11.18±8.94
TBUT
Preoperative	10.11±1.41	9.87±1.28	9.93±1.35
1 month postoperative	6.21±1.27‡	6.32±1.39‡	6.68±1.43‡
3 months postoperative	7.38±1.19‡	7.56±1.43‡	7.92±1.52‡
6 months postoperative	8.03±1.46‡	8.09±1.62‡	9.61±1.51*,**
12 months postoperative	9.27±1.25	9.31±1.38	9.81±1.34
24 months postoperative	9.43±1.60	9.57±1.54	9.88±1.37
36 months postoperative	9.72±1.39	9.81±1.61	9.91±1.23

Notes: Data are mean ± SD.

‡ Statistically significant difference from the preoperative value,

* statistically significant difference from the LASIK group,

** statistically significant difference from the FS-LASIK group.

Abbreviations: LASIK, laser in situ keratomileusis; FS-LASIK, femtosecond laser-LASIK; SMILE, small incision lenticule extraction; CH, corneal hysteresis; CRF, corneal resistance factor; OSDI, ocular surface disease index; TBUT, tear breakup time.

Figure 1 Preoperative (pre-op) and postoperative (post-op) corneal hysteresis (CH) changes in the three groups.

Abbreviations: LASIK, laser in situ keratomileusis; FS-LASIK, femtosecond laser-LASIK; SMILE, small incision lenticule extraction.

Figure 2 Preoperative (pre-op) and postoperative (post-op) corneal resistance factor (CRF) changes in the three groups.

Abbreviations: LASIK, laser in situ keratomileusis; FS-LASIK, femtosecond laser-LASIK; SMILE, small incision lenticule extraction.

Figure 3 Preoperative (pre-op) and postoperative (post-op) ocular surface disease index (OSDI) changes in the three groups.

Abbreviations: LASIK, laser in situ keratomileusis; FS-LASIK, femtosecond laser-LASIK; SMILE, small incision lenticule extraction.

Figure 4 Preoperative (pre-op) and postoperative (post-op) tear breakup time (TBUT) changes in the three groups.

Abbreviations: LASIK, laser in situ keratomileusis; FS-LASIK, femtosecond laser-LASIK; SMILE, small incision lenticule extraction.