Table 2

Volumetric reproducibility of optic disc variables measured by TopSS

VariableSD CV (%)
Contour variation (mm)0.0398.3
Mean contour depth (mm)0.0127.3
Cup shape0.0287.9
Effective area (mm2)0.0473.9
1/2 depth area (mm2)0.0626.8
C/D ratio 0.0194.0
NRRA (mm2)0.0574.7
Volume above (mm3)0.0178.9
Volume below (mm3)0.0234.0
1/2 depth volume (mm3)0.0188.3
Average depth (mm)0.0194.3
Maximum depth (mm)0.0495.0
Average slope (degree)1.2252.9
Maximum slope (degree)0.8291.4
  • CV = coefficient of variation; C/D = cup/disc; NRRA = neuroretinal rim area.