Figure 6: The effect of axial length on the accuracy of ETDRS thickness plots. For each subject, we compared the raw ETDRS thickness plot assuming a 6 mm scan size to an ETDRS thickness plot using a scan length corrected for their axial length. As the deviation in axial length increases, the error in ETDRS thickness plots (sum of all nine ETDRS segments) becomes greater, both for the normal subjects (open circles) and the pathology subjects (crosses).