Objectives:
To compare the measurements obtained by partial coherence interferometry (PCI) (AL Scan, Nidek) and optical low coherence reflectometry (OLCR) (Lenstar, Haag-Streit AG) and to evaluate the inter-device differences with respect to deviation from target refraction.
Materials and Methods:
The medical charts of the patients who underwent cataract surgery between January 2013 and February 2013 in our department were retrospectively evaluated. Forty-two eyes with ultrasonographic biometry, PCI, and OLCR measurements performed in the same visit were included in the study. Ophthalmological and systemic findings of the patients, axial length (AL), anterior chamber depth (ACD), intraocular lens (IOL) power calculations recommended for emetropy, and keratometry measurements (K1, K2) in all eyes, and deviations from target refraction in 20 eyes were noted.
Results:
The mean age of the patients was 68.00±13.15 years; female/male ratio was 7/20. There were no statistically significant differences between the two devices with respect to AL, K2, and recommended IOL power measurements, whereas ACD measured by PCI was 0.02 mm more shallow and K1 values in PCI were 0.27 D steeper (p=0.003 and p=0.037, respectively). There was a good correlation between the measurements of the two devices (p<0.0001). Moreover, deviations from target refractions measured at 1 week and 1 month did not differ significantly between the two devices (p=0.152 and p=0.181, respectively).
Conclusion:
It is important to know the correlation and differences between measurements obtained by different biometry devices. In our study, as measurements of PCI and OLCR correlated well despite the negligible differences, we suggest that both methods can be used interchangeably.
Keywords: IOL power calculation, partial coherence interferometry, optical low coherence reflectometer, refractive deviation