Comparison of Corneal Thickness Measurements with Optical Low Coherence Reflectometry, Orbscan System and Ultrasound Pachymeter

ABSTRACT

PURPOSE: To investigate the accuracy and reproducibility of Optical Low Coherence Reflectometry (OLCR) corneal thickness measurements compared with the Orbscan system and ultrasound pachymeter (IOPac, Mentor). METHODS: Two examiners measured corneal thicknesses of 78 normal eyes and in 36 eyes that had undergone LASIK, and five sequential measurements of corneal thickness with OLCR, Orbscan system, Mentor, and IOPac were performed. Remeasurements of corneal thickness in 24 normal eyes were performed after two days to investigate intra-examiner reproducibility. RESULTS: The average corneal thickness measured in normal subjects was 536.3+/-23.8 micrometer in OLCR, 542.4+/-25.3 micrometer in the Orbscan system, 535.4+/-23.7 micrometer in Mentor, and 534.2+/-24.1 micrometer in IOPac. The average corneal thickness measured in patients who had undergone LASIK was 487.3+/-30.8 micrometer in OLCR, 492.5+/-36.5 micrometer in the Orbscan system, 487.5+/-30.8 micrometer in Mentor, and 485.3+/-30.8 micrometer in IOPac. There was no statistically significant difference between the four pachymeters. The inter-examiner and intra-examiner reproducibilities were shown to be highly reliable. CONCLUSIONS: The OLCR showed similar measurments of corneal thickness with the Orbscan system and ultrasound pachymeter, and showed no difference in reproducibility with different examiners.