High-frequency ultrasound biomicroscopy versus ultrasound and optical pachymetry for the measurement of corneal thickness.

The aim of this study was to correlate central corneal thickness measurements obtained using optical as well as ultrasound pachymeters and high-frequency ultrasound biomicroscopy (UBM), assuming UBM as reference. Each measurement was performed on 32 patients (60 eyes) by three observers unaware of the other's results, on 3 different days. Pearson correlation was used. A strong correlation was found between UBM and ultrasound pachymetry measurements (r=0.858), a weaker one between UBM and optical pachymetry (r=0.506). Optical versus ultrasound measurements were poorly correlated (r=0.540). Each correlation was statistically significant (p<0.001). UBM can be used as an accurate and reproducible method for determining corneal thickness.