Corantin Maurin, Sylvain Poinard, Gauthier Travers, Zhiguo He, Fanny Decoeur, Etienne Gontier, Georgia Karpathiou, Philippe Gain, Gilles Thuret, French Fuchs Study Group
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.
AIM: 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).
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.