A simulation procedure for stereological correction of early AMD lesion sizes observed in single OCT-B-scans

PURPOSE: Early lesions caused by age-related macular degeneration (AMD) are imaged by optical coherence tomography (OCT) in unprecedented detail. Most probably, however, the sampling plane of an OCT scan meets a given lesion noncentrally, and the observed sizes of its diameter, cross-sectional area, and volume must be stereologically corrected. METHODS: Stereological corrections are obtained by a simulation procedure, which is applied to the leading scans in a consecutive sample of 100 early AMD participants. RESULTS: Mean corrections for lesion diameter, cross-sectional area and volume amount to +9.1%, +32.0%, and +46.6%, respectively. After correction, AMD stage classifications with respect to the 125-µm diameter cutpoint had to be changed for seven participants. CONCLUSIONS: Simulation results confirm that for lesions pictured and measured in OCT scans - regardless of the accuracy of OCT imaging - stereological correction of observed sizes is compelling and unavoidable. TRANSLATIONAL RELEVANCE: Categorial AMD classifications based on observed OCT data must be reexaminated after stereological correction.