effect of software upgrade on optical coherence tomography measurement of the retinal nerve fiber layer thickness

ABSTRACT

To determine the effect of software upgrades on retinal nerve fiber layer [RNFL] thickness measurements taken by spectral domain optical coherence tomography [SD-OCT]. Eighty normal eyes [40 patients] were scanned for RNFL thickness measurements using Spectralis [Heidelberg Engineering, Heidelberg, Germany] SD-OCT. Scan analysis was performed using version 4.0 software and then reanalyzed with version 5.1.3. Student paired t testing and Pearson's correlation coefficient were used for statistical analysis. Average and quadrant RNFL thicknesses generated using version 4.0 and 5.1.3 software on Spectralis demonstrated high correlation [r = 0.955-0.998]. Average RNFL thickness using version 4.0 was 0.08micro m thinner than version 5.1.3 [p = 0.409]. Quadrant RNFL differences ranged from -0.26 to +0.97 microm [p = 0.146-0.915]. Segmentation errors were reduced 33% after the upgrade. Minor RNFL thickness changes may occur after software upgrades in Spectralis OCT. The differences did not reach statistical significance but segmentation errors were improved