comparison of central corneal thickness measured by anterior segment optical coherence tomography, pentacam and ultrasonic pachymetry

AIM: To investigate and analyze the differences in central corneal thickness(CCT)measurement by anterior segment optical coherence tomography(AS-OCT), pentacam rotating Scheimpflug camera and ultrasonic pachymetry(USP).

METHODS: The retrospective study measured CCT of 43 patients(86 eyes)performed excimer laser myopia corrective surgery by the same examiner using RTVue AS-OCT with an anterior segment adaptor, pentacam rotating Scheimpflug camera, and PACSCAN300P USP. Data of three groups were compared and statistically analyzed by pair t test.

RESULTS: The mean CCT(±SD)measured by AS-OCT,pentacam and USP were 535±52, 550±52, 550±51μm, respectively. Paired-sample t test showed that the results of AS-OCT, pentacam and USP were statistically different. There were no statistically significant differences in the mean CCT between the pentacam and USP group. Significant correlations of measurement result were found between pentacam and USP(r=0.998, P<0.01), FD-OCT and USP(r=0.993, P<0.01), and AS-OCT and pentacam(r=0.991, P<0.01).

CONCLUSION:RTVue AS-OCT significantly under estimates the CCT, while the measurement results by pentacam are similar to those by USP which is regarded as the golden standard.