Comparison of material seen in Bruch’s membrane, entrapment sites, and membranous debris
| Deposit | Site | Ultrastructural features on EM |
|---|---|---|
| Bruch’s membrane change | predominantly OCZ | coated membrane bound bodies intact or ruptured |
| Entrapment sites | rest on ICZ | as above |
| raise RPE bm | coated membrane bound bodies | |
| Membranous debris | three sites: | coiled membranes |
| (1) internal to RPE bm | bilayered structure of lipids | |
| (2) within RPE bm | not coated | |
| (3) external to RPE bm | ||
| only in presence of BLD |
EM = transmission electron microscopy; OCZ = outer collagenous zone of Bruch’s membrane; ICZ = inner collagenous zone of Bruch’s membrane; RPE bm = basement membrane of the retinal pigment epithelium; BLD = basal laminar deposit.