The comparison of corneal thickness measurement: ultrasound versus optical methods.

ABSTRACT

PURPOSE: To compare the measurement of central corneal thickness between ultrasonic and optical techniques in normal Thai myopic eyes. METHOD: In this prospective study, the ultrasonic and optical pachymeter were employed to measure the central corneal thickness in 100 eyes of normal myopic volunteers. Corneal thickness was compared using the paired Student t-test. The correlation of central corneal thickness between the two groups was assessed by linear regression analysis. RESULTS: The difference of mean central corneal thickness between ultrasound (554.4 +/- 27.50 microm) and optical (581.1 +/- 22.62 microm) pachymetry was statistically significant in the normal myopic eyes (p = 0.001). Both methods possessed a highly significant linear correlation (r = 0.90, p = 0.001). CONCLUSIONS: The optical measurement of central corneal thickness in normal myopic eyes is, on average, 27 microm greater than ultrasonic pachymeter measurement.