In Vivo Confocal Microscopic Findings in Posterior Polymorphous Corneal Dystrophy

Purpose To describe the corneal findings in posterior polymorphous corneal dystrophy (PPCD) as imaged with laser scanning in vivo confocal microscopy (IVCM). Methods IVCM images of 7 subjects with PPCD who had typical slit-lamp biomicroscopic findings of endothelial vesicular, band, and/or placoid lesions were evaluated. Results Five women and 2 men aged 7 to 64 years were included in this study. Laser scanning IVCM (Heidelberg Retina Tomograph II, Rostock Cornea Module) revealed hyporeflective, round, vesicular lesions with diameters ranging between 20 and 200 µm in 3 subjects, combined vesicular and curvilinear hyperreflective band-like lesions in 3 subjects, and combined vesicular and placoid hyperreflective lesions in 1 subject at the level of Descemet membrane (DM), endothelial cell layer, and posterior stroma adjacent to DM. One subject had coassociated epithelial basement membrane dystrophy. Additional findings included posterior stromal keratocytes with elongated spindle-like nucleus, giant and nucleated endothelial cells, endothelial deposits, and guttae-like dark spots. The mean endothelial cell density was 1485.7 ± 486.3 cells per square millimeter (range, 990-2365 cells/mm). The mean central corneal thickness was 585.3 ± 37.17 μm (range, 534-643 μm). Conclusions Laser scanning IVCM is able to highlight the characteristic microstructural alterations at the level of endothelium and DM in the setting of PPCD and may have diagnostic utility in equivocal cases with borderline biomicroscopic findings. The possible association of PPCD with epithelial basement membrane dystrophy warrants further investigation.