Appendix2660021169012 Rev. A 2017-12 CIRRUS HD-OCT User ManualC-8Table C-6: Mean Difference between CIRRUS HD-OCT 5000 and Visante OCT for thePost-LASIK GroupThese tables show that the central cornea as measured using the pachymetry scan hasmuch better repeatability and agreement with Visante OCT than the central cornealthickness as measured with the Anterior Chamber scan. The improved performance is likelydue to the fact that the pachymetry measurement averages over a 3mm central area, whilethe Anterior Chamber scan depends on subjective placement of the scan directly over thecentral cornea for a single measurement. For this reason, we recommend using thepachymetry scan to get the best possible estimate of central corneal thickness.NOTE: Measurements made with the CIRRUS HD-OCT Anterior Segment scans should notbe directly compared with Visante OCT measurements.Scan Type CIRRUS Visante Difference 95% CI 95% LOAParameter N Mean (SD) Mean (SD) Mean (SD) Mean Difference p-value Mean DifferencePachymetryCenter 40 465.6 (44.3) 463.7 (44.8) 1.8 (6.1) -0.1, 3.8 0.064 -10.3, 13.9Inner Nasal 40 515.8 (39.8) 515.8 (38.9) 0.0 (14.7) -4.7, 4.7 1.000 -29.4, 29.4Inner Superior 40 509.5 (39.6) 515.6 (39.4) -6.2 (13.6) -10.5, -1.8 0.007 -33.4, 21.1Inner Inferior 40 500.6 (39.1) 499.2 (39.2) 1.4 (10.8) -2.1, 4.9 0.418 -20.2, 23.0Inner Temporal 40 481.7 (39.0) 490.7 (38.5) -9.0 (9.5) -12.0, -6.0 <.001 -28.0, 10.0Outer Nasal 40 584.8 (35.3) 591.9 (36.1) -7.2 (19.3) -13.3, -1.0 0.024 -45.7, 31.4Outer Superior 40 580.7 (35.3) 595.9 (35.6) -15.3 (18.5) -21.2, -9.4 <.001 -52.2, 21.6Outer Inferior 40 562.5 (35.1) 569.1 (37.2) -6.6 (17.9) -12.3, -0.9 0.025 -42.5, 29.3Outer Temporal 40 529.8 (33.6) 552.0 (34.9) -22.3 (16.4) -27.5, -17.0 <.001 -55.0, 10.5N is the number of eyes with measurements.Difference = CIRRUS - Visante.ACD of Visante was adjusted by CCT (i.e. ACD = original ACD - CCT/1000).95% confidence interval (CI) for mean difference is based on t-distribution.p-value is based on paired t-test.95% Limits of Agreement (LOA) = mean difference ± 2 x difference SD.
