Three-dimensional topography of Descemet's membrane in Fuchs endothelial corneal dystrophy using laser scanning confocal microscopy and white-light interferometry.

Abstract

To evaluate the potential of a three-dimensional microscope combining laser scanning confocal imaging and white-light interferometry for quantitative topographic characterisation of Descemet's membrane (DM) in Fuchs endothelial corneal dystrophy (FECD). Descemet's membranes were collected from 38 FECD patients undergoing endothelial keratoplasty and four healthy donors. After flat-mounting on glass slide and drying, specimens were analysed using the VK-X3000 system (KEYENCE). Entire samples were reconstructed by image stitching at low magnification (×10) in white-light interferometry mode (0.01 nm axial resolution). Higher magnifications (×20 to ×150) in confocal mode (12 nm axial resolution) enabled detailed structural analysis. Three-dimensional height maps were generated to calculate standardised surface roughness parameters. Guttae and other DM features were classified according to spatial organisation and elevation profiles. White-light interferometry enabled full-field mapping of whole 8 mm diameter DMs with nanometric vertical resolution (~2 hours/sample). Surface roughness (Sa) was higher in FECD than in controls (median±IQR: 0.571±0.259 µm vs 0.239±0.161 µm; p=0.0018). In FECD, three zones were identified: centre (guttae buried in the posterior fibrillar layer; Sa 0.442±0.112 µm), paracentre (large uncovered guttae; Sa 0.562±0.170 µm; p=0.0423) and outer zone (no confluent guttae; Sa 0.261±0.143 µm; p<0.0001). Confocal three-dimensional (3D) imaging revealed radial striae, embossments and furrows in the DM, confluent central guttae and fused or buried structures. Combining white-light interferometry and confocal microscopy enables label-free, high-resolution surface characterisation of DM in FECD, providing quantitative metrics to compare histological subtypes and supporting the predominance of radial structural organisation.