|
 |
 |
|
Soft Drusen: Formation and Regression 1. Svetlana Cherepanoff 1. Anatomical Pathology, Prince of Wales Hospital, Randwick, Australia PURPOSE: To describe the "life cycle" of soft drusen by correlating their light and electron microscopic features to clinical fundus appearances and other histopathological hallmarks of METHODS: Eighty eyes (50 patients) with histopathologically defined soft drusen were selected from a large clinicopathological series described in detail elsewhere. Electron micrographs (26 eyes) and 8-40 light microscopy sections (54 eyes) were reviewed. Soft drusen size and contents were correlated with clinical fundus appearance and the following features: basal lamina deposit (BLamD), retinal pigment epithelial (RPE) abnormalities and unsuspected choroidal neovascularisation (CNV). RESULTS: Soft drusen were only found in eyes with: (i) continuous BLamD (ii) geographic atrophy (GA); or (iii) disciform scarring (DS). Drusen regression was characterised histologically by increasingly granular contents, drusen collapse, calcification and replacement by fibroblasts or other cells, and was associated with late-type thick continuous BLamD and increasing RPE abnormalities. Clinically, regressing drusen appeared yellower or whiter with more distinct margins, pigment changes (single clump, stippling, or a pigment figure) and focal loss of RPE leaving foci of calcification. Focal subclinical CNV was found in 32% of GA eyes with soft drusen. CONCLUSION: Soft drusen appear to follow a cycle of formation and regression, first appearing as small, membranous (also termed lipoprotein-derived debris) accentuations of basal linear deposit when a continuous layer of BLamD is present. Drusen regression is associated with late type BLamD and RPE failure, seen clinically as regressing drusen with pigment changes and later as fading drusen with focal RPE loss. |
 |