3D model of pterygium and corneal limbus: Investigating histopathology and stem cell distribution

Purpose This study aims to create a complete histological 3D computer model of pterygium in situ, mapping the anatomy of the disease tissue, its relation to the corneal limbus and the distribution of limbal stem cells. Methods One human eye affected with pterygium was obtained from a cornea donor post mortem. The anterior part of the eye was cut into 900 consecutive horizontal sections. Every other section was stained with HE to be digitized, aligned and 3D reconstructed using interactive 3D visualization software. Immunohistochemistry targeting CK19, MMP-1, p63 and VEGF was performed on the remaining sections alternating across the structure so as to create evenly distributed overlaying models. Results Using the sections a high-resolution model of the pterygium and limbus was created, and in aligning the immunostained sections to the model, a spatial map of the staining was created.Analyzsing the model we found a mostly normal temporal limbus with intact architecture, however nasally the limbus was found to be buried under the pterygial mass and only partly intact, showing a number of pathological changes. Conclusions The limbal degeneration underneath the pterygium appears to be a precondition for or a consequence of the pterygial growth.