Significance of Hyperreflective Foci as an Optical Coherence Tomography Biomarker in Retinal Diseases: Characterization and Clinical Implications

Figure 2

Spectral-domain optical coherence tomography (SD-OCT) B-scans illustrating hyperreflective foci (HRF) in age-related macular degeneration (AMD). (a) SD-OCT B-scan of intermediate AMD demonstrating a large HRF overlying confluent drusen located just above the external limiting membrane within the outer nuclear layer (inset, yellow arrowhead). HRF may represent migrating retinal pigment epithelium cells or a nascent type 3 lesion. Nascent lesions can be differentiated from type 3 macular neovascularization for the absence of exudative changes, as intraretinal fluid and cystic changes on OCT B-scans. (b) SD-OCT B-scan showing a case of macular neovascularization with multiple HRF located in the subretinal space and outer plexiform layer (inset, yellow arrowheads), probably of microglial origin, and more interestingly associated with a subretinal lipid globule. This novel OCT feature appears as a roundish hyporeflective structure (inset, purple ellipse) with a characteristic hypertransmission tail (white arrow), which is originated from a lensing effect produced by a lipidic content [74].