Why the color disparity?

83-year-old man with Dry Age Related Macular Degeneration and an Epiretinal Membrane. The epiretinal membrane accounts for the mild retinal thickening and a focal area of retinal atrophy accounts for the loss of the ellipsoid band on cross-sectional imaging. Interestingly, the ILM-RPE thickness average subfield map does not match color-by-color to the ILM-RPE point-by-point colorimetric overlay representation. This is because the point-by-point overlay map represents the retinal thickness for this individual patient while the average map is color coded according to differences between this patient and age-matched controls.