Figure 6. High magnification transmission electron micrograph of the third and fifth drusen phenotypes

The third drusen phenotype exhibits granular material with large amounts of electron dense and electron lucent material, as well as calcium-containing inclusions (A). A fifth phenotype of drusen exhibits numerous membrane-bounded vesicles (B and Figure 7B) and possesses material with a periodicity similar to that of basal laminar deposit/long-spacing collagen, which is interspersed within these vesicles (B). No granular material or other characteristics typical of the other four drusen phenotypes is observed in this class.