Agreement of Central Corneal Thickness Measurements Using two Different Ultra Sound Techniques

Purpose: To compare the Central Corneal Thickness (CCT) measurements obtained by Ultrasound Pachymeter (USP) & Ultrasound Biomicroscope (UBM). Methods: The study CCT measurements of 60 eyes was measured using first with UBM followed by USP. Results were compared statistically using Bland –Altman plots & Deming’s regression analysis Results: Scatter plot analysis showed that for the same value of CCT UBM , corresponding CCTP measurements vary systematically. Bland – Altman plot analysis showed that there is systematic difference between the measurements with both instruments. Deming’s regression analysis confirmed a reasonable agreement between both two measurements. Conclusion: There is a positive correlation in our study & the readings obtained by UBM correlate with that measured by Pachymeter. But since the interobserver variability is high with UBM, pachymeter is considered to be a better modality of measurement of CCT among the two of them.