Ultrasound and partial coherence interferometry with measurement of central corneal thickness.
OBJECTIVE
To compare noncontact pachymeter measurements with ultrasound pachymeter measurements and assess their reproducibility.


METHODS
Central corneal thickness was measured in 104 eyes of 56 patients with three laser interference pachymeters (OLCR [Haag Streit, Könitz, Switzerland], OCP [4optics AG, Lübeck, Germany], and ACMaster [Carl Zeiss Meditec, Jena, Germany]) and an ultrasound pachymeter (Tomey AL2000 [Tomey Corp, Nagoya, Japan]).


RESULTS
Compared to the ultrasound measurements, the mean difference for the laser interference pachymeter measurements were +8.8 microm (standard deviation [SD] 5.68) for the OLCR, -8.0 microm (SD 5.39) for the OCP, and -0.12 microm (SD 5.88) for the ACMaster. Reproducibility could only be estimated as not all of the devices allowed access to individual measurements. For all laser interference devices, reproducibility was estimated to be approximately 2 microm. Ultrasound measurements yielded a reproducibility of approximately 3.4 microm.


CONCLUSIONS
Although ultrasound pachymeter measurements differed significantly from OLCR and OCP measurements, agreement was considered good because the mean differences were <10 microm, and the results can be regarded as clinically interchangeable.
Much
Martin Michael
MM
University Eye Hospital, Julius-Maximilians-Universität Würzburg, Würzburg, Germany. m.much@augenklinik.uni-wuerzburg.de
Haigis
Wolfgang
W
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry / Q000379:methods*; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D007368:Interferometry / Q000379:methods*; D008027:Light; D008875:Middle Aged; D015203:Reproducibility of Results; D014465:Ultrasonics; D014463:Ultrasonography