Comparison of central corneal thickness measurements with optical low-coherence reflectometry and ultrasound pachymetry and reproducibility of both devices.

PURPOSE

To compare the accuracy of optical low-coherence reflectometry (Lenstar LS 900; Haag Streit, Köniz, Switzerland) and conventional ultrasound pachymetry (UP) (US 4000; Nidek, Japan) for measuring central corneal thickness and to assess the interexaminer reproducibilities of both devices.

METHODS

Department of Ophthalmology, Selcuklu Faculty of Medicine, Selcuk University was the study setting. Central corneal thickness (CCT) was measured in both eyes of 65 emmetropic patients by the same examiner using Lenstar LS 900 noncontact biometry and UP. To assess the interexaminer reproducibility, 2 different examiners consecutively obtained CCT measurements in 16 eyes with Lenstar LS 900 noncontact biometry and UP.

RESULTS

Mean CCT measurements with Lenstar LS 900 noncontact biometry and ultrasound biometry were 541.09 ± 33.8 and 545.69 ± 34.0, respectively. Significant correlation was present between these 2 measurements; intraclass correlation coefficient was found to be 95.8% (95% confidence interval: 93.2%-97.4%)(P < 0.001). Interexaminer reproducibility with Lenstar was high, and the intraclass correlation was found to be 99.3% (95% confidence interval: 98.0%-99.7%). We have also investigated the interexaminer reproducibility with UP in these 16 patients, and the results showed a 99.2% (95% confidence interval: 97.7%-99.7%) intraclass correlation.

CONCLUSIONS

The results of Lenstar LS 900 noncontact biometry correlated with the results of UP. It may be used as an alternative method to UP for measuring CCT. Because of the mild underestimation of CCT by Lenstar, the measurements should be carefully evaluated in patients whose intraocular pressure must strictly be monitored.