Corneal Epithelial Thickness Mapping Adds Precision to RCE Care

CET mapping provides a potentially more accurate and detailed assessment of RCE compared to fluorescein staining, identifying larger lesion areas—particularly detecting abnormalities in the central and upper cornea—that staining may overlook. These images from the study show the value of CET in a 19-year-old RCE patient who had previously undergone corneal epithelial debridement twice: (A) External eye photography of the affected eye, taken with direct illumination. (B) External eye photography of the affected eye with fluorescein staining. (C) CET mapping of the affected eye. (D) Manual delineation of the lesion areas identified by fluorescein (green) and CET mapping (orange). Photo: Huang W-L, et al. Transl Vis Sci Technol. April 9, 2026. Click image to enlarge. Accurately identifying the extent of abnormal epithelium in patients with recurrent corneal erosion (RCE) is crucial for selecting the appropriate surgical approach and preventing postoperative recurrence. Recently, researchers from Taiwan compared a new method using corneal epithelial thickness (CET) mapping on OCT to the traditional approach of corneal fluorescein staining. They found that CET mapping provides a potentially more accurate and detailed assessment of recurrent erosion compared to staining, identifying larger lesion areas—particularly detecting abnormalities in the central and upper cornea—that staining may overlook. The findings were reported in Translational Vision Science & Technology.A total of 15 RCE patients underwent same-day external eye photography and AS-OCT. Fluorescein staining lesions were manually delineated, and CET lesions were identified by marking regions with a thickness ≥60μm. The two methods were compared retrospectively. Patients with extensive lesions identified by CET underwent phototherapeutic keratectomy (PTK) after manual epithelial debridement, with clinical outcomes and CET map findings evaluated.Epithelial thickness mapping consistently identified significantly larger lesion areas than fluorescein staining. The median difference in lesion size between the two methods was 9.26mm². This discrepancy likely relates to the detection of subclinical epithelial edema or uneven hydration rather than frank epithelial adhesion defects alone. “We hypothesize that, in areas adjacent to active erosions, the epithelium may already be loosened or poorly anchored, leading to localized fluid accumulation and subsequent thickening on the CET map,” the researchers explained in their paper. “Because these areas of subclinical edema have not yet resulted in a complete break in the epithelial surface, they do not take up fluorescein stain, and their thickness change may be too subtle to be identified as negative staining.” Consequently, CET mapping provides a more comprehensive view of the “at-risk” epithelium,they say,  revealing a broader field of basement membrane instability that necessitates treatment to prevent future recurrence.While both methods were strongly correlated (r=0.904), CET mapping frequently detected lesion extensions—particularly in the superior and paracentral zones—that were not visible with fluorescein. This pattern was consistent across both groups of disease entities, including trauma-related and non–trauma-related RCE. “Clinically, this is highly significant, as the location and extent of the lesions can substantially influence the choice of treatment approach and scope,” the authors wrote. “For example, smaller lesions that do not involve the central cornea are more suitable for needle or YAG laser anterior stromal puncture. Identification of a more extensive epithelial involvement on CET mapping may favor surface-regularizing treatments such as PTK, which can address broader epithelial–stromal interface.”In cases where fluorescein staining indicated only inferior corneal involvement, CET mapping revealed superior extension in 50% of those cases, offering a more precise basis for treatment planning.PTK was performed on nine patients. Follow-up evaluations showed no recurrences, and CET maps indicated a smoothing and normalization of the corneal epithelium. This underscores the importance of accurate lesion identification and proper treatment selection in effectively managing RCE, according to the researchers. “It is noteworthy that, in post-PTK eyes, the detection of the epithelium may be interfered with by the ablated anterior stroma, resulting in delineation error and artifacts,” they wrote. Further longitudinal studies regarding epithelial recovery after PTK may aid the understanding of the dynamic remodeling process of the corneal surface and help establish objective, time-dependent CET mapping criteria to distinguish physiological healing from true pathological recurrence.The researchers concluded that epithelial thickness mapping is a sensitive, reliable tool for identifying RCE lesions that enables more accurate treatment planning and improved management outcomes. The study recommends incorporating CET mapping into the clinical workflow for RCE patients.Click here for the journal source. Huang W-L, Chien J-H, Chen L-Y, et al. Anterior segment optical coherence tomography epithelial thickness mapping for lesion delineation in recurrent corneal erosion: a paired-method study. Transl Vis Sci Technol. April 9, 2026. [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.