Scheimpflug Backscatter Imaging of the Fibrillar Layer in Fu
A central collagen-rich subendothelial fibrillar layer (FL) correlates with areas of accentuated loss of corneal endothelial cells in advanced Fuchs endothelial corneal dystrophy (FECD). A Study was conducted to investigate if the FL may be visualized by en face Scheimpflug backscatter imaging in vivo.

34 eyes undergoing Descemet membrane endothelial keratoplasty (DMEK) surgery with preoperative high-quality Scheimpflug backscatter imaging data were included. The Descemet endothelium complex (DEC) was retrieved during DMEK surgery and immunofluorescence staining was performed for collagens I, III, and IV.

Scheimpflug backscatter imaging delineated the FL in n=26 eyes and was FL-negative in n=8 eyes with deviation compared to immunofluorescence in one case and good agreement of morphology characteristics.

--Horizontal caliper diameter±standard deviation was 4.84±0.85mm, vertical caliper diameter was 3.92±0.78mm, maximum caliper diameter was 5.12±0.82mm and surface area was 12.43±4.74mm2.

--Compared to immunofluorescence imaging, mean difference and ICC were for horizontal caliper diameter 0.13mm and 0.88, vertical caliper diameter 0.23mm and 0.81, maximum caliper diameter 0.06mm and 0.86 and surface area 1.4 mm2 and 0.85.

Conclusively, Scheimpflug backscatter imaging allows for better visualization of the FL in advanced FECD eyes, perhaps allowing for in vivo identification of sick parts of the FECD endothelium.