In-vivo Three-Dimensional Confocal Laser Scanning Microscopy of Corneal Surface and Epithelium

Background/aims: To evaluate in vivo three-dimensional (3-D) confocal laser scanning microscopy (CLSM) as a technique for visualising the corneal surface and epithelium. Methods: Ten human corneas (three from healthy volunteers, three with bullous keratopathy, three from patients following penetrating keratoplasty, and one with corneal erosion) were examined by 3-D CLSM. A novel polymethyl methacrylate (PMMA) contact cap was designed to minimise artefacts due to applanation pressure. Results: 3-D reconstruction and different visualisation techniques (volume rendering, cross-section, en face view, oblique section and surface reconstruction) were performed to demonstrate alterations to corneal surface and epithelium. Image quality (cell identification, motion blur, absence of compression artefacts, imaging of superficial structures and of subepithelial nerve plexus) was considerably superior to that obtained using a conventional contact cap with a planar surface. Conclusions: 3-D CLSM permits in vivo visualisation and analysis of the corneal surface and of spatial arrangement at the cellular level in epithelium in normal and pathological corneas. The novel design of the contact cap minimises artefacts due to applanation pressure and improves the image quality of epithelial structures. The method provides a basis for further in vivo studies of alterations to corneal surface structure and its cellular arrangement.