Table 2

Average IVCM parameters, corneal sensitivity and DC parameters in the SMILE and tPRK groups before and after surgery

SMILE						tPRK
Parameter		S _pre	S _1w	S _1m	S _3m	P value	T _pre	T _1m	T _3m	P value
CNFD (n/mm²)	Operated eye	15.46±2.59	1.69±2.02***	3.04±2.11***	4.96±5.02***	<0.001	15.41±7.48	1.01±1.38***	0.99±0.88***	<0.001
CNFD (n/mm²)	Unoperated eye	15.64±5.20	13.09±5.31	13.39±6.24	15.47±5.65	0.315	16.45±5.51	13.23±4.31	11.64±6.33	0.180
CNBD (n/mm²)	Operated eye	15.63±5.71	0.95±1.90***	1.74±1.98***	4.41±6.78***	<0.001	14.73±11.89	0.62±0.64**	0.64±0.89**	0.006
CNBD (n/mm²)	Unoperated eye	15.49±8.44	12.32±7.73	14.26±9.28	16.91±8.46	0.107	13.29±7.07	10.66±6.44	14.13±15.09	0.355
CNFL (mm/mm²)	Operated eye	11.46±1.46	3.99±1.65***	4.62±1.30***	5.59±2.87***	<0.001	11.69±3.10	4.75±1.05***	4.88±1.11***	<0.001
CNFL (mm/mm²)	Unoperated eye	11.45±2.15	10.37±2.31	10.65±2.79	11.92±2.32	0.062	12.08±2.49	10.56±2.34	10.33±3.57	0.173
CTBD (n/mm²)	Operated eye	29.09±8.09	9.18±5.00^‡	9.97±5.11***	13.66±10.32***	<0.001	27.78±13.38	15.83±6.01*	16.20±5.30*	0.027
CTBD (n/mm²)	Unoperated eye	28.88±9.68	25.56±9.52	27.98±13.97	33.33±11.78	0.046	17.10±9.83	25.39±9.76	30.09±23.54	0.676
CNFA (mm²/mm²)	Operated eye	0.0053±0.0010	0.0029±0.0010***	0.0030±0.0008***	0.0035±0.0014***	<0.001	0.0055±0.0014	0.0045±0.0014**	0.0036±0.0012	0.014
CNFA (mm²/mm²)	Unoperated eye	0.0052±0.0008	0.0052±0.0009	0.0052±0.0014	0.0061±0.0016	0.059	0.0055±0.0019	0.0057±0.0014	0.0062±0.0035	0.794
CNFW (mm/mm²)	Operated eye	0.0221±0.0010	0.0279±0.0020***	0.0261±0.0016***	0.0255±0.0027***	<0.001	0.0220±0.0010	0.0320±0.0029***	0.0316±0.0021***	<0.001
CNFW (mm/mm²)	Unoperated eye	0.0219±0.0009	0.0227±0.0013**	0.0222±0.0012	0.0222±0.0011	0.017	0.0216±0.0008	0.0225±0.0011	0.0228±0.0018	0.074
CNFrD	Operated eye	1.442±0.030	1.319±0.060***	1.337±0.041***	1.356±0.063***	<0.001	1.437±0.053	1.368±0.038**	1.363±0.030**	0.002
CNFrD	Unoperated eye	1.448±0.024	1.431±0.031	1.435±0.037	1.450±0.038	0.106	1.449±0.272	1.427±0.038	1.429±0.049	0.150
Corneal sensitivity (cm)	Operated eye	5.952±0.075	5.148±0.117***	5.367±0.201***	5.595±0.222***	<0.001	5.92±0.08	5.10±0.15***	5.24±0.13***	<0.001
Corneal sensitivity (cm)	Unoperated eye	5.967±0.058	5.824±0.170**	5.876±0.118*	5.943±0.103	0.003	5.95±0.05	5.83±0.14**	5.82±0.23	0.009
DC density (cells/mm²)	Operated eye	15.44±15.41	20.79±29.85	14.01±16.02	24.03±36.86	0.488	14.68±14.24	23.37±16.11	20.48±13.78	0.399
DC density (cells/mm²)	Unoperated eye	14.47±13.56	21.45±16.49	31.37±37.55	39.54±36.31*	0.028	16.89±12.76	20.74±15.62	22.44±26.85	0.595
DC area (µm²)	Operated eye	30.39±14.79	54.89±32.93**	44.55±25.19*	42.32±20.78	0.004	34.55±8.51	44.48±21.36	34.28±17.47	0.353
DC area (µm²)	Unoperated eye	32.61±11.64	45.48±17.52*	48.30±14.95**	43.36±13.77*	0.003	33.58±19.53	45.04±22.21	39.30±26.95	0.390

*P<0.05, **p<0.01, ***p<0.001.
The p values for each group are obtained by comparing the postoperative values at each time point with the preoperative values and corrected using Bonferroni correction.
CNBD, corneal nerve branch density; CNFA, corneal nerve fibre area; CNFD, corneal nerve fibre density; CNFL, corneal nerve fibre length; CNFrD, corneal nerve fibre fractal dimension; CNFW, corneal nerve fibre width; CTBD, corneal nerve total branch density; DC, dendritic cell; IVCM, in vivo laser scanning confocal microscope; 1m, 1 month; 3m, 3 months; SMILE, small incision lenticule extraction; S_pre, preoperative SMILE group; T_pre, preoperative tPRK group; tPRK, transepithelial photorefractive keratectomy; 1w, 1 week.