Directional Optical Coherence Tomography Imaging of Macular Pathology

Abstract

Purpose: To survey the impact of directional reflectivity on structures within optical coherence tomography (OCT) images in retinal pathology. Methods: Sets of commercial OCT images taken from multiple pupil positions were analyzed. These Directional OCT (D-OCT) sets revealed directionally reflective structures within the retina. After ensuring sufficient image quality, resulting hybrid and composite images were characterized by assessing the Henle Fiber Layer (HFL), Outer Nuclear Layer (ONL), Ellipsoid Zone (EZ), and Interdigitation Zone (IZ). Additionally, hybrid images were reviewed for novel directionally reflective pathological features. Results: Cross-sectional D-OCT image sets were obtained in 75 eyes of 58 subjects having a broad range of retinal pathologies. All cases showed improved visualization of the ONL/Henle fiber layer interface, and ONL thinning was therefore more apparent in several cases. The EZ and IZ also demonstrated attenuation where a geometric impact of underlying pathology affected their orientation. Misdirected photoreceptors were also noted as a consistent direction-dependent change in EZ reflectivity between regions of normal and absent EZ. Conclusion: D-OCT enhances the understanding of retinal anatomy and pathology. This optical contrast yields more accurate identification of retinal structures and possible imaging biomarkers for photoreceptor-related pathology.