Panel Proposes Standardized Nomenclature for AS-OCT Findings

The rise of anterior segment optical coherence tomography (AS-OCT) has enabled eye doctors to visualize and assess the anterior structures of the eye with high-definition, cross-sectional images. While this technology is increasingly helpful for understanding conditions affecting the ocular surface, tear film, cornea and anterior chamber structures, the lack of standardized anatomical terminology hampers clinical consistency and comparison of findings across studies.To address this challenge, a group of experts from ophthalmology, optometry and vision science has come together to create consensus-based nomenclature for ocular structures imaged by AS-OCT. Building on the success of the Advised Protocol for OCT Study Terminology and Elements (APOSTEL) for posterior segment OCT, the new APOSTEL-AS will adapt these standards for anterior segment imaging. Over the last 12 months, investigators gathered insights into the application of AS-OCT across various ocular conditions, leading to the proposal of 45 anatomical terms for consideration. A total of 14 experts participated in the consensus panel. Using a nominal group technique, the panel reached a minimum agreement threshold of 80% for the terms proposed. Seven cross-sectional AS-OCT images were selected for review.The panel agreed upon 31 of the initial 45 proposed terms for annotation of identifiable structures. This consensus encompassed a variety of key ocular structures, including the cornea, lens and conjunctiva. In their paper on the study, published last week in JAMA Ophthalmology, the researchers noted, “Unanimity was reached for almost all annotations across both swept-source and spectral-domain OCT images, supporting applicability of this nomenclature across a diverse group of clinicians and researchers.”1 Fourteen experts in the fields of ophthalmology, optometry and vision science shared the above images denoting various anatomical landmarks on anterior segment OCT. Adoption of this terminology throughout the profession, they argue, will help improve diagnostic precision, disease monitoring, clinical documentation and inter-center communication. Photos ©2025 Fraser AS, et al. JAMA Ophthalmology. Click each image to enlarge.However, challenges were noted in achieving consensus for structures that were difficult to visualize in vivo (such as the palisades of Vogt and episcleral and scleral vasculature), suggesting the need for ongoing dialogue and research in these areas.The authors of an invited commentary on the study, also published in JAMA Ophthalmology, noted that many of the 31 proposed terms “were revised in cases where the original labels implied an anatomical precision level exceeding the imaging resolution capacities (e.g., ciliary body muscle instead of ciliary body radial fibers).”2 The inability to achieve consensus on the remaining terms, they explained, primarily stemmed from differing views on whether the current AS-OCT imaging platforms could reliably and accurately identify or delineate specific anatomical microstructures. For instance, “the embedded limbus palisades of Vogt could be difficult to consistently and clearly delineate with the current AS-OCT penetration,” the commentary authors noted. Another example, they added, is Schlemm’s canal and scleral venous sinus; “the two adjacently located, lumen-shaped structures could be challenging to differentiate, especially if the image quality is suboptimal.”2Despite the lack of consensus on these annotations, the authors of the study wrote that this “does not preclude the future capture of these structures with newer or modified OCT platforms.”1 As these devices and image analysis tools continue to evolve, consensus development will be an ongoing process, they noted.Limitations of this research include the inherent challenges of achieving consensus among experts, the process of which may oversimplify complex anatomical features in the pursuit of standardization. The study also lacked sufficient input from lower-income countries affected by anterior segment diseases. Furthermore, the commentary highlights the possible influence of differences between imaging devices and their impact on inter-study comparisons.In conclusion, the researchers wrote, “By establishing a unified language for describing anterior segment structures, this APOSTEL-AS initiative has addressed a gap that might hamper communication across the research and clinical communities.”1 Click here for the study source and here for the commentary. 1. Fraser AS, Ang M, Bellchambers A, et al. Proposed nomenclature for landmarks in anterior-segment OCT: The APOSTEL-AS Panel Consensus. JAMA Ophthalmol. August 14, 2025. [Epub ahead of print]. 2. Chan PP, Chan JY, Cheung CY. Invited commentary: Establishing consensual terms of AS-OCT anatomical landmarks. JAMA Ophthalmol. August 14, 2025. [Epub ahead of print].  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.