Effect of Optical Coherence Tomography Scan Pattern and Density on the Detection of Full-Thickness Macular Holes

Abstract

To evaluate the impact of different scan patterns and scan densities on small full-thickness macular hole (MH) detection. Retrospective cross-sectional analysis. Analysis was performed on 25 eyes from 24 patients with full-thickness MHs imaged with the Heidelberg Spectralis HRA+OCT. Included eyes underwent concurrent imaging with a standard (61-line) raster volume and a 24-line radial pattern. A 6-line radial scan pattern was extrapolated from the higher-density radial pattern. Comparisons of the missed hole rate as well as the proportion of individual B-scans demonstrating a full-thickness defect (termed "full-thickness detection index") were carried out for the 3 scan patterns. Additionally, qualitative and quantitative hole parameters were evaluated to identify factors associated with "missed" holes. Full-thickness defects were missed at substantially higher rates using both standard raster volume (20.0%, 90% confidence interval [CI] 8.2%-37.5%) and 6-line radial scanning (12.0%, 90% CI 3.7%-30.4%) when compared to 24-line radial scanning (0% for both comparisons). Full-thickness detection indices were significantly higher for both radial scan patterns when compared to raster scanning (P < .001 for both comparisons). Missed holes were smaller and commonly associated with prehole flaps. High-density radial scanning demonstrated superior detection rates of small full-thickness MHs compared to standard raster volume scanning. This finding may be attributable to the greater foveolar scan density attained with radial scan patterns. Failure to utilize radial scanning in the setting of suspected macular holes may lead to a delay in surgical treatment, with attendant worse anatomic and visual outcomes.