Proposed lexicon for anatomic landmarks in normal posterior segment spectral-domain optical coherence tomography: the IN•OCT consensus

Abstract

Purpose: To develop a consensus nomenclature for the classification of retinal and choroidal layers and bands visible on spectral-domain optical coherence tomography (SD-OCT) images of a normal eye.

Design: An international panel with expertise in retinal imaging (International Nomenclature for Optical Coherence Tomography [IN • OCT] Panel) was assembled to define a consensus for OCT imaging terminology.

Participants: A panel of retina specialists.

Methods: A set of 3 B-scan images from a normal eye was circulated to the panel before the meeting for independent assignment of nomenclature to anatomic landmarks in the vitreous, retina, and choroid. The outputs were scrutinized, tabulated, and used as the starting point for discussions at a roundtable panel meeting. The history of anatomic landmark designations over time was reviewed for the various cellular layers of the ocular structures that are visible by SD-OCT. A process of open discussion and negotiation was undertaken until a unanimous consensus name was adopted for each feature.

Main outcome measures: Definitions of normal eye features showed by SD-OCT.

Results: Definitions for various layers changed frequently in the literature and were often inconsistent with retinal anatomy and histology. The panel introduced the term "zone" for OCT features that seem to localize to a particular anatomic region that lacks definitely proven evidence for a specific reflective structure. Such zones include the myoid, ellipsoid, and the interdigitation zones.

Conclusions: A nomenclature system for normal anatomic landmarks seen on SD-OCT outputs has been proposed and adopted by the IN • OCT Panel. The panel recommends this standardized nomenclature for use in future publications. The proposed harmonizing of terminology serves as a basis for future OCT research studies.