Abstract
Optic disc drusen (ODD) are acellular calcified deposits within the optic nerve head. They arise early in life, usually remain asymptomatic with a benign prognosis, and they are most often clinically relevant as they can be mistaken for papilloedema, can result in asymptomatic optic nerve thinning resembling glaucoma, or can have complications such as anterior ischaemic optic neuropathy with sudden loss of vision. There is still a lot of uncertainty about the pathogenesis of ODD, and prognostic factors for vision loss in the long term. The strongest association of ODD is with pseudoxanthoma elasticum, a condition of systemic ectopic calcification. Understanding the shared biochemical pathways underlying pseudoxanthoma elasticum and other conditions with the same phenotype, highlights pyrophosphate as an important factor in ectopic calcification and a potential therapy.