Commentary on: Navigating pediatric corneal imaging: Contextualizing Anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in the assessment of congenital corneal opacities
Year: 2025
Type: editorial
Abstract: Congenital corneal opacities (CCOs) represent a significant clinical challenge in pediatric ophthalmology and are often accompanied by anterior segment dysgenesis and complex developmental anomalies. Diagnostic clarity in these cases hinges on precise anterior segment imaging, which influences both the prognosis and surgical planning. Against this backdrop, the study by Yangzes et al.[1,2], comparing anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) for pachymetry and topographic assessment in pediatric CCO, is a timely and methodologically sound contribution to the pediatric imaging literature. This well-executed, single-center study involving 54 eyes of 34 children provides quantitative comparisons of central corneal thickness (CCT) and qualitative insights into the feasibility, repeatability, and limitations of these technologies in a pediatric cohort. The results have broad clinical implications for follow-up strategies, surgical planning, and modality selection in children with CCOs.[3–5] The authors meticulously compared pachymetric measurements derived from both modalities and highlighted that the values are not interchangeable in the setting of CCO. The mean pachymetric discrepancy of ~66 µm (UBM > AS-OCT) is statistically and clinically significant, particularly when considering the implications for intraocular pressure assessment and longitudinal monitoring. The lack of agreement is well demonstrated through the Bland–Altman analysis and reflects the fundamental differences in imaging physics between light-based AS-OCT and sound-based UBM.[6] Perhaps, one of the most clinically relevant aspects of this study is the expanded role of AS-OCT. In addition to pachymetry, the authors successfully obtained keratometry and corneal topography data in over 70% of the eyes—an achievement of particular note in pediatric opaque corneas, where conventional topography often fails. These findings provide valuable insights into the curvature and astigmatism of abnormal corneas, enhancing preoperative evaluation, prognostication, and parental counseling. Nevertheless, UBM remains a crucial diagnostic tool, especially in cases where dense opacity or anterior segment distortion limits the utility of AS-OCT. UBM’s superior tissue penetration enables visualization of retro-corneal structures, posterior corneal curvature, and iridocorneal adhesions, which are often critical for diagnostic precision and surgical planning, particularly in cases such as Peters anomaly, anterior staphyloma, and congenital aphakia.[7,8] A key strength of this study is its rigorous methodology. Imaging was performed by a single experienced examiner to ensure consistency. The phenotypic diversity included (Peters anomaly, sclerocornea, cornea plana, and congenital aphakia) strengthens generalizability, and subgroup analysis reinforces the uniformity of the discrepancy direction across conditions. Limitations, such as the absence of reproducibility metrics and the difficulty of co-localizing imaging spots across modalities, are transparently acknowledged. Importantly, this study also contributes to the understanding of pediatric keratometry in abnormal corneas, reporting steep keratometric values consistent with those in the previous literature.[5,6] However, in ~28% of cases, anatomical distortion prevented the acquisition of reliable AS-OCT curvature maps, reminding clinicians of the real-world limitations of this powerful modality. The study effectively demonstrated that AS-OCT and UBM yield noninterchangeable pachymetric measurements in pediatric CCOs, with UBM consistently producing higher CCT values by ~66 µm. While AS-OCT can acquire corneal topography and keratometry in the majority of cases, it is limited in certain anatomically distorted or densely opaque eyes. Conversely, UBM remains an essential imaging modality in such cases because of its superior tissue penetration and capacity to delineate retro-corneal and posterior segment structures. These findings underscore the importance of maintaining consistency in the choice of imaging modality during longitudinal follow-up to ensure the reliability and comparability of data across time points.[2] Given its noncontact, rapid acquisition and suitability for outpatient settings, AS-OCT presents clear logistical and safety advantages for routine and serial imaging, particularly in infants and toddlers, where the risks and logistical challenges of sedation are significant. This makes it especially valuable for postoperative monitoring and tracking the progression of disease. In contrast, regarding UBM, although it generally necessitates anesthesia in young children, it offers indispensable structural detail in anatomically complex cases. It is best employed in scenarios involving diagnostic ambiguity, surgical planning, or dense opacity limiting the utility of optical imaging. The findings of this study underscore the importance of adopting a modality-specific imaging strategy tailored to the patient’s clinical profile and imaging goals. While AS-OCT may serve as the default tool for routine follow-up, UBM plays a critical role in more challenging diagnostic scenarios.[2,5,6] This study paves the way for multiple avenues of future research that could enhance the utility and reliability of pediatric imaging. Key areas include the evaluation of intra- and inter-observer reproducibility for both AS-OCT and UBM, which would help to validate their clinical robustness.[2,4–6,9] Objective grading systems for opacity density may further clarify the limitations of each modality for different corneal phenotypes. The integration of artificial intelligence, particularly for image registration and alignment, can address the current challenges of comparing data across imaging platforms. Moreover, prospective clinical trials correlating imaging biomarkers with surgical outcomes and visual rehabilitation would provide functional relevance to anatomical measurements. Additionally, future advancements in swept-source AS-OCT, such as real-time eye tracking and motion correction, could significantly improve imaging reliability in uncooperative or very young pediatric patients, thereby expanding its clinical applicability.[6,8] In summary, Yangzes et al.[2] provide methodologically sound and clinically valuable insights into the complementary roles of AS-OCT and UBM in the assessment of pediatric CCOs. The demonstrated noninterchangeability of measurements between these modalities necessitates a consistent, patient-specific imaging strategy. Their respective advantages—the noncontact and outpatient feasibility of AS-OCT and the high-resolution, penetrating capability of UBM—underscore the importance of tailoring modality selection to individual clinical contexts. As anterior segment imaging continues to evolve, such comparative analyses will be instrumental in shaping standardized protocols and enhancing the quality of pediatric ophthalmic care.
Source: Indian Journal of Ophthalmology
Author: Muralidhar Ramappa
Institution: L V Prasad Eye Institute
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4413816536