Effect of OCT B-Scan Density on Sensitivity for Detection of Intraretinal Hyperreflective Foci in Eyes with Age-Related Macular Degeneration.

To evaluate the impact of reducing the density of B-scans in an optical coherence tomography (OCT) volume on the sensitivity for detecting intraretinal hyperreflective foci (IHRF) in eyes with intermediate age-related macular degeneration (AMD). A total of 165 eyes with intermediate AMD and IHRF were evaluated in this retrospective analysis. For each case, Cirrus HD-OCT volumes were imported into the reading center 3 D-OCTOR software. The number of IHRF cases was assessed based on all 128 B-scans (spaced 47 μm apart), using a categorical scale (graded as 1-4, 5-9, 10-14, 15-19, and >20). Additionally, the B-scan densities in the volume were lowered to 64 B-scans (spaced 94 μm apart), 43 B-scans (spaced 140 μm apart), and 32 B-scans (spaced 188 μm apart). The number of eyes with any IHRF and the numerical category of IHRF in the eye were used to compare the sensitivity at each reduced B-scan density against the reference 128 B-scan volume. In the primary analysis for the qualitative presence or absence of any IHRF, the sensitivity decreased to 98.2% ( Increasing the inter-B-scan spacing from 47 to 188 microns significantly reduced the ability to accurately determine whether IHRF were present in an eye. An increase in inter-B-scan spacing to 140 microns was associated with a significant misclassification of the IHRF quantity. These findings may be relevant in the design of OCT scanning protocols for studies utilizing these biomarkers for AMD progression.