Comparison of central corneal thickness measurements between anterior chamber-optical coherence tomography and ultrasonic pachymeter

Objective: To assess the agreement of central corneal thickness (CCT) measured by anterior chamber-optical coherence tomography (AC-OCT) and ultrasonic pachymeter and provide an objective basis for clinical application of AC-OCT. Methods: CCT of 150 college student volunteers (300 eyes) measured by two devices were obtained. The data was analyzed by paired t test and Pearson correlation analysis. Bland-Altman plot and Mountain plot were used to assess the agreement. Results: The mean CCT values were (530.05 ± 33.611) μm measured by AC-OCT and (543.68 ± 35.088) μm measured by ultrasonic pachymeter. Regression analysis showed a high correlation between the values obtained by both devices (r=0.960, P<0.001). Compared with AC-OCT, ultrasonic pachymeter overestimated the CCT by a mean of 13.62 μm. The two modalities had incomparable results. Conclusion: It is important to be noted in clinical practice that the measurements acquired by these two modalities are not directly interchangeable. However, the CCT measurements by the AC-OCT and ultrasonic pachymeter are highly correlated. AC-OCT is an effective method to observe the changes of the corneal thickness in the long term. (authors)