Table 1: Central corneal thickness measurements with ultrasound pachymetry and spectral-domain optical coherence tomography at 3 time points before ultraviolet A irradiation.

Mean CCT USP
(range) (microns)
Mean CCT SDOCT
(range) (microns)
Mean TCT SDOCT
(range) (microns)

Baseline
(440–510)

(435–539)

(395–480)
After epithelial removal
(388–460)

(390–498)

(356–430)
After 30 minutes of riboflavin
(302–369)

(303–396)

(249–341)

CCT: central corneal thickness; TCT: thinnest corneal thickness; USP: ultrasound pachymetry; SDOCT: spectral-domain optical coherence tomography.
Values in microns are presented as mean ± standard deviation (range).
values are for comparison with ultrasonic pachymetry.