Drusen (singular, druse) are tiny yellow or white accumulations of extracellular material that build up between Bruch's membrane and the retinal pigment epithelium of the eye.hether drusen promote AMD or are symptomatic of an underlying process that causes both drusen and AMD is not known, but they are indicators of increased risk of the complications of AMD. 'Hard drusen' may coalesce into 'soft drusen' which is a manifestation of macular degeneration.