Table 3.

Paired t-test results and correlation of Orbscan and Pentacam in curvature readings in 5 corneal rings.

Orbscan and Pentacam	1 mm ring	2 mm ring	3 mm ring	4 mm ring	5 mm ring
Mean difference ± SD	−2.01 ± 2.70	−1.72 ± 2.43	−1.34 ± 2.04	−0.90 ± 1.50	−0.32 ± 1.46
P-valuea	P < 0.0001	P < 0.0001	P < 0.0001	P < 0.0001	0.12
Correlation (Pearson's coefficient)	0.89	0.90	0.91	0.93	0.90
P-valueb	P < 0.0001	P < 0.0001	P < 0.0001	P < 0.0001	P < 0.0001

SD: Standard deviation.

^aThe P-value was calculated by paired t-test.

^bThe P-value for correlation coefficient.