CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12Appendix B-5images, the identification of layers is different, so the CIRRUS HD-OCT is expected toprovide a thicker measurement than the Stratus OCT.cáÖìêÉ=_JN==píê~íìë=l`q=_JëÅ~å=ëÜçïáåÖ=äçÅ~íáçåë=çÑ=omb=~åÇ=fij=ä~óÉêëcáÖìêÉ=_JO==`foorp=eaJl`q=_JëÅ~å=ëÜçïáåÖ=äçÅ~íáçåë=çÑ=omb=~åÇ=fij=ä~óÉêëBecause of this difference in segmentation strategy, there is a mean difference in theretinal thickness found by each instrument. Furthermore, because the integrity of the layerssought varies with pathology, the mean difference between instruments varies withpathology, as can be seen in Table B-4. Even after the mean difference has beenaccounted for, there is a residual difference that can be seen in the standard deviation ofthe difference reported in the last column of Table B-4. Because of the residualdifference, it is better to compare scans between Stratus OCT and CIRRUS HD-OCTqualitatively, looking for changes in retinal morphology, rather than making decisionsbased on quantitative evaluation.
