Posters

Comparison of predictability and accuracy of corneal thickness measurements between 3 pachymetry platforms and ultrasound pachymetry in Asian eyes

Poster Details

First Author: O.Chng SINGAPORE

Co Author(s):    S. Teoh   S. Tan   S. Yau   L. Cheong   E. Wong        

Abstract Details

Purpose:

The purpose of this study is to compare the accuracy and comparison in cornea central thickness (CCT) readings between the Ultrasound pachymetry, Orbscan IIz, Galilei dual Scheimpflug analyser and the Visante Anterior Segment Optical Coherence Tomography (ASOCT).

Setting:

Single center, Public hospital in Asia

Methods:

A prospective study of 75 Asian patients (150 eyes). All patient had their CCT measured in the following order, Orbscan IIz (Bausch & Lomb), followed by Galilei-Dual Scheimpflug analyzer (Ziemer), Anterior Segment Optical Coherence Tomography (Visante) and lastly with the Ultrasound pachymetry (US-1800 Echoscan Nidek). The results from all 3 machines were compared with the Ultrasound pachymetry. Bland-Altman plots were used to evaluate the agreement between the instruments.

Results:

The mean measurements of average CCT by Ultrasound pachymetry, Orbscan IIz, Galilei and ASOCT were 555.7 +/- 36.8 um, 575.9 +/- 37.3um, 574.4 +/- 35.3 and 548.4 +/- 37.5um. The mean difference for CCT measurements between ASOCT and Ultrasound pachymetry were -7.32um (95% C.I -9.04 to -5.60um), between Galilei and Ultrasound pachymetry were 18.65um (95% C.I 15.81 to 21.48um) and between Orbscan IIz and Ultrasound pachymetry were 20.17 (95% C.I 16.45 to 23.89um). The mean difference for CCT measurements between Galilei and Orbscan IIz were -1.52um (95% C.I -4.64 to 1.60um){p >0.05}.

Conclusions:

The ASOCT underestimated CCT compared to that measured with Ultrasound pachymetry in Asian eyes. The Orbscan IIz and Galilei had better agreement with each other but overestimated CCT compared to that measured with Ultrasound pachymetry in Asian eyes. Clinicians should be aware of these discrepancies when using these instrument to measure CCT in Asian eyes.

Financial Disclosure:

NONE