Evaluation of corneal epithelial thickness mapping via spectral-domain OCT in patients after allogeneic haematopoietic stem cell transplantation

Background Ocular chronic graft versus host disease (oGVHD) seriously affects ocular surface, which often results in corneal epithelial damage. The purpose of this study is to evaluate corneal epithelial thickness (CET) via spectral-domain optical coherence tomography (SD-OCT) in patients who underwent allogeneic haematopoietic stem cell transplantation (HSCT). Methods This study included 30 post-HSCT patients along with 20 healthy participants. CET and corneal thickness mapping were performed via SD-OCT and were obtained in multiple predefined corneal regions, namely, the central, superior, inferior, temporal and nasal zones, including both mid and the peri zones. Lid margin irregularity was assessed, and its correlation with CET was evaluated. Statistical analyses, including one-way analysis of variance and Pearson correlation, were used to assess group differences and correlations between CET and lid margin irregularity. Results Significant differences in corneal CET were observed between post-HSCT patients and healthy controls in several corneal regions, with thinning noted in multiple zones, particularly in the superior and inferior areas, prior to the clinical diagnosis of chronic oGVHD. Additionally, a positive correlation was observed between lid margin irregularity and CET in several peripheral regions, indicating that lid margin changes may contribute to alterations in epithelial distribution. Conclusion The CET map demonstrated that post-HSCT patients with or without chronic oGVHD had a relatively thicker corneal epithelium in the central and inferior regions. These changes were correlated with lid margin morphology. This SD-OCT mapping provides a better understanding of early corneal epithelial alterations following HSCT and identifies potential biomarkers for early diagnosis.