Retinal Optical Coherence Tomography Imaging Biomarkers: A Review of the Literature

Abstract Purpose: This literature review aims to summarize novel optical coherence tomography (OCT) imaging biomarkers that have recently been described in the literature and are frequently encountered clinically. Methods: The literature was reviewed to identify novel OCT biomarkers reported to date. A descriptive summary of all terms and representative illustrations were provided to highlight the most relevant features. Results: 37 OCT terminologies were identified. The vitreomacular interface disorders group included the four stages of ERM, macular pseudohole, tractional LH, degenerative LH, cotton ball sign, and foveal crack sign. The AMD group included outer retinal tubulation, multi-layered pigment epithelial detachment, pre-choroidal cleft, onion sign, double-layer sign, complete outer retinal atrophy, complete RPE and outer retinal atrophy, and reticular pseudodrusen. Uveitic disorders group consisted of bacillary layer detachment, syphilis placoid, rain cloud sign, and pitchfork sign. The disorders relating to toxicity group included flying saucer sign and MEK inhibitor-associated retinopathy. The disorders associated with systemic conditions group included choroidal nodules and needle sign. The pachychoroid spectrum group included pachychoroid and brush border pattern. The vascular disorders group included pearl necklace sign, diffuse retinal thickening, disorganization of retinal inner layers, INL microcysts, hyperreflective retinal spots, paracentral acute middle maculopathy, and acute macular neuroretinopathy. The miscellaneous group included omega sign (ω), macular telangiectasia (type 2), and omega sign (Ω). Discussion: 37 OCT terminologies were summarized and detailed illustrations consolidating the features of each biomarker were included. A nuanced understanding of OCT biomarkers and their clinical significance is essential due to their predictive and prognostic value.