• Written By: Rahul Khurana, MD

    An international panel of experts in vitreoretinal diseases and imaging has proposed a new classification system to describe the various hypo- and hyperreflective features visible in spectral-domain OCT scans of normal eyes.

    With the latest improvements in imaging allowing unprecedented detail of the retina and choroid, there is a need for a consensus nomenclature for OCT findings in normal eyes. The goal of the International Nomenclature for Optical Coherence Tomography [IN•OCT] Panel was to codify current understanding and provide a framework to integrate future developments.

    The panel’s review found that definitions for various retinal and choroidal layers changed frequently in the literature and were often inconsistent with retinal anatomy and histology.

    While the panel readily agreed on many anatomic correlates, other features required careful logical parsing of numerous possibilities. In the absence of recognized specific evidence to assign an attribution, the term “zone” was used along with the local anatomic region. This avoided the problem of overspecification of the attribute in the absence of exacting proof. They describe the zones as the myoid, ellipsoid and interdigitation zones.

    The panel considers this a dynamic classification system, requiring continuous updating based on improvements in OCT technology and new discoveries.

    At the same time, it is hoped that it will facilitate communication in the field today. As optical coherence tomography morphed from a research instrument available to a select few to a common tool in clinical practice, with many treatment algorithms heavily dependent on the findings of tomographic imaging, there is a pressing need for the construction of a pragmatic and consistent glossary of terms constituting an OCT lexicon.