Clinical Outcomes Comparison of Combined Small Incision Lenticule Extraction with Collagen Cross-Linking Versus Small Incision Lenticule Extraction Only

Table 2

The safety indices (postoperative CDVA/preoperative CDVA) and efficacy indices (postoperative UDVA/preoperative CDVA) of both groups at 6, 12, and 24 months.

	6 months	12 months	24 months
Safety index
SMILE	1.11 ± 0.20	1.03 ± 0.23	1.07 ± 0.16
SMILE xtra	1.09 ± 0.19	1.07 ± 0.15	1.03 ± 0.08
value	0.737	0.414	0.369
Efficacy index
SMILE	1.02 ± 0.15	1.01 ± 0.23	1.05 ± 0.16
SMILE xtra	1.01 ± 0.19	1.05 ± 0.15	1.00 ± 0.00
value	0.842	0.503	0.223