Drusen morphometrics on optical coherence tomography in eyes with age-related macular degeneration and normal aging.

Abstract

To compare drusen size metrics (apical height and basal width) on optical coherence tomography (OCT) B-scans with their size assessed on color photos in eyes with age-related macular degeneration (AMD) and normal aging. A total of 508 drusen were evaluated in this analysis. Flash color fundus photos (CFP), infrared reflectance (IR) images, and OCT B-scans obtained at the same visit were evaluated. Individual drusen were identified on CFPs and the diameters of the drusen were measured in planimetric grading software. CFPs were manually registered to the IR image with their corresponding OCT volume. After confirming correspondence between the CFP and OCT, the apical height and basal width of the same drusen were measured on OCT B-scans. Drusen were divided into small, medium, large, and very large categories based on their diameter on the CFP images (< 63, 63 to 124, 125 to 249, and [Formula: see text] 250μm, respectively). The OCT apical height of small drusen on CFP ranged from 20 to 31μm, while medium drusen ranged from 31 to 46μm, large drusen ranged from 45μm to 111µm, and very large drusen ranged from 55μm to 208μm. The OCT basal width measured < 99μm in small drusen, from 99 to 143μm in medium drusen, from 141 to 407µm in large drusen, and > 209µm in very large drusen. Drusen of different size categories on color photographs may also be separated according to their apical height and basal width on OCT. The apical height and basal width ranges defined in this analysis may be of value in the design of an OCT-based grading scale for AMD.