Table 3.

Pre- and Postoperative Comparison of Corvis ST Parameters

Parameter		Mechanical Epi-Off CXL	P Value	tPTK-asst. Epi-Off CXL	P Value	Wf-Guided tPRK CXL	P Value	P Valuea	P Valueb	P Valuec
CVS-CT	Preoperative	484 ± 34	<0.001	508 ± 31	<0.001	505 ± 30	<0.001
	Postoperative	462 ± 39		484 ± 36		474 ± 24
	Mean difference	−22 ± 18		−25 ± 21		−31 ± 16		1.0	0.175	0.564
	(95% CI)	(−27 to −17)		(−31 to −18)		(−37 to −24)
bIOP, mm Hg	Preoperative	13.4 ± 2.4	<0.001	13.6 ± 1.8	<0.001	13.2 ± 2.0	<0.001
	Postoperative	15.4 ± 3.1		15.4 ± 2.3		16.0 ± 2.4
	Mean difference	2.03 ± 2.21		1.8 ± 2.2		2.8 ± 2.1		1.0	0.861	0.394
	(95% CI)	(1.4 to 2.7)		(1.1 to 2.5)		(2.0 to 3.6)
IIR, mm−1	Preoperative	12.1 ± 2.0	<0.001	10.8 ± 1.8	<0.001	10.8 ± 1.6	0.005
	Postoperative	11.3 ± 1.9		10.2 ± 1.7		10.4 ± 1.5
	Mean difference	−0.7 ± 0.9		−0.6 ± 1.1		−0.4 ± 0.7		1.0	0.476	1.0
	(95% CI)	(−1.0 to −0.5)		(−0.9 to −0.2)		(−0.7 to −0.1)
SSI	Preoperative	0.78 ± 0.18	0.005	0.88 ± 0.17	0.014	0.89 ± 0.18	0.014
	Postoperative	0.83 ± 0.21		0.94 ± 0.18		0.99 ± 0.29
	Mean difference	0.05 ± 0.12		0.05 ± 0.13		0.09 ± 0.19		1.0	0.822	0.820
	(95% CI)	(0.01 to 0.09)		(0.01 to 0.09)		(0.02 to 0.16)

Data are expressed as mean ± standard deviation and mean differences additionally with 95% confidence intervals (95% CI).

bIOP, biomechanical-corrected intraocular pressure; CVS-CT, corneal thickness measured with Corvis ST; IIR, integrated inverse radius; SSI, stress strain index.

Statistical significance (P < 0.05) is marked in bold face.

^a P value between mechanical epi-off CXL and tPTK-asst. epi-off CXL.

^b P value between mechanical epi-off CXL and Wf-guided tPRK CXL.

^c P value between tPTK-asst. epi-off CXL and Wf-guided tPRK CXL.