Table 4

Intra (within) centre agreement analysis (direct clinical measurements with patients in attendance)

Groups comparedNoMean difference95% CI for
mean difference
TL as %
of range
Crude ICCAdjusted ICC
RCRS1v RCRS2 R3880.10.01, 0.190.881.750.980.98
RCRS1v RCRS2 L3880.10.00, 0.200.981.960.980.98
RCRS1v RCRS3 R3880.40.31, 0.490.911.850.970.98
RCRS1v RCRS3 L3880.30.20, 0.401.042.060.970.97
RCRS2v RCRS3 R3880.30.22, 0.380.831.640.980.98
RCRS2v RCRS3 L3880.10.01, 0.190.871.750.980.98
RCRS1v RCRS2 R4000.1−0.65, 0.857.1414170.830.83
RCRS1v RCRS2 L4000.3−0.58, 1.188.5817270.780.78
CO1v CO2 R1660.2−1.03, 1.438.2516220.800.80
CO1v CO2 L1660.8−0.13, 1.736.1512130.890.89
  • Unmasked measurements performed in rapid sequence; RCRS1 = research clinic reference standard first observation; RCRS2 = research clinic reference standard second observation; RCRS3 = research clinic reference standard third observation; CO1 = community optometric first assessment; CO2 = community optometric second assessment; R = right eye; L = left eye; SD = standard deviation of paired differences; CI = confidence interval (for the mean); TL = tolerance limit for change; ICC = intraclass correlation coefficient.