Comparison of Three Methods of Measuring Corneal Thickness and Anterior Chamber Depth
Accepted 22 August 2005. published online 05 October 2005.
Purpose
To compare three different methods of measuring corneal thickness (CT) and anterior chamber depth (ACD).
Design
Prospective clinical trial (Medical University of Vienna, Austria).
Methods
Central CT (CCT), CT at four peripheral points, and central ACD were measured in 88 eyes of 44 healthy subjects with the Pentacam (rotating Scheimpflug camera; Oculus, Wetzlar, Germany), Orbscan I (scanning-slit topography system; Orbtek Inc, Salt Lake City, Utah, USA), and AC-Master (partial coherence interferometry; Zeiss Meditec, Jena, Germany), and the results were compared.
Results
The upper (lower) limits of agreement for CCT measurements were 7.9 (−22.2) μm between AC-Master and Pentacam, 17.6 (−32.5) μm between AC-Master and Orbscan, and 25.2 (−25.9) μm between Pentacam and Orbscan. Correlation was high between all three methods (r = 0.94 to 0.97). The upper and lower limits of agreement for ACD were 0.174 (−0.251) mm between AC-Master and Pentacam, 0.406 (−0.004) mm between AC-Master and Orbscan, and 0.384 (0.095) mm between Pentacam and Orbscan. Correlation was high between the three methods (r = 0.96 between Orbscan and Pentacam; others 0.92). Correlation was lower for the CT measurements at the four peripheral points.
Conclusions
The CCT and ACD values obtained by Pentacam, Orbscan, and AC-Master measurements correlated well and showed few outliers. The two new systems (Pentacam, AC-Master) provide a reliable, easy-to-use, noncontact method of measuring CCT and ACD. Larger differences occurred only when measuring peripheral CT values, especially between AC-Master and the other two methods.
aDepartment of Ophthalmology, Medical University of Vienna, Vienna, Austria.
bDepartment of Medical Physics, Medical University of Vienna, Vienna, Austria.
Inquiries to Oliver Findl, MD, Department of Ophthalmology, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Wien, Austria; fax: +43-1-40400-7881
1 W.D. is a consultant for Carl Zeiss Meditec (Jena, Germany).
ABSTRACT