Abstract Purpose 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… Click to show full abstract
Abstract Purpose 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) Methods 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. Results In the primary analysis for the qualitative presence or absence of any IHRF, the sensitivity decreased to 98.2% (p = .32) with 64 B-scans, 92.7% (p = .001) with 43 B-scans, and 75.2% (p = .001) with 32 B-scans, compared with the 128 B-scan reference. With regard to the number of IHRF per eye, there was a significant difference (with a lower level chosen on the scale) when the B-scan density was reduced to 43 or 32 B-scans (p = .002 and p < .001, respectively). Conclusion 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.
               
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