Agreement between extrapolated corneoscleral topographical data obtained during natural and retracted eyelid positions

Eyelid retraction substantially increased data coverage for the 12.5 and 15.0 mm chord diameters. Significant differences in the extrapolated sagittal height data generated from measurements obtained during natural and retracted eyelid positions were observed for the superior location (12.5, 15.0 and 17.5 mm chord diameters) and inferior and nasal locations (17.5 mm chord diameter). Extrapolated sagittal height values obtained during the natural eyelid position were typically greater than those obtained with eyelid retraction, most likely due to the amount of measured data available for extrapolation.