Imaging modalities in optic disc drusen: A literature review and proposed diagnostic algorithm

Optic disc drusen (ODD) concern highly prevalent anatomical features that are increasingly recognised as a risk factor for various pathological conditions. In clinical practice, differentiation between ODD and true papilloedema poses considerable challenges, often resulting in the effectuation of unnecessary, potentially invasive examinations. Furthermore, recent years have witnessed a notable expansion in imaging modalities employed to map ODD, primarily novel optical coherence tomography (OCT) modalities. A growing necessity arises for literature providing a profound comparison between most of the various available techniques, as well as furnishing clinicians with practical guidelines to manage a patient with suspected ODD. A comprehensive search of the current literature formed the foundation of this narrative review. We primarily focused on data from recent studies, each of which was thoroughly analysed and interpreted by all the authors. We formulate a straightforward diagnostic model to approach a patient with suspected ODD, wherein a primary distinction is made between patients with a high and low suspicion for papilloedema. Enhanced Depth Imaging OCT (EDI-OCT) emerges as the most potent modality and is thus recommended as the new gold standard technique. Fluorescein angiography exhibits excellent specificity and therefore proves useful to exclude papilloedema, although not with full certainty. Fundus autofluorescence and ultrasonography appear to be most beneficial for screening purposes and in a population with very low suspicion of papilloedema. This narrative review is the first to present a clinically relevant diagnostic model to discriminate between ODD and papilloedema, identifying EDI-OCT as the primary imaging modality in ODD diagnosis.