Optic disc drusen: understanding an old problem from a new perspective

Abstract

Optic disc drusen (ODD) are acellular deposits located in the optic nerve head of up to 2.4% of the population. They may develop as by-products of impaired axonal metabolism in genetically predisposed individuals, in whom a narrow scleral canal is hypothesized to play a role. Although ODD are often considered as benign innocent bystanders, recognized as part of a routine ophthalmological examination, the vast majority of patients with ODD have visual field defects. Optic disc drusen (ODD)-associated complications with severe visual loss, most often due to anterior ischaemic optic neuropathy, are also known to occur. There are no treatments available to prevent or ameliorate the vision loss caused by ODD. In children, the ODD are usually uncalcified and buried within the optic nerve head tissue. In these cases, the condition can be difficult to diagnose, as it often resembles a papilloedema with optic nerve head swelling caused by raised intracranial pressure. During the teenage years, the ODD progressively become more calcified and probably also larger, which allow them to be visible on ophthalmoscopy. With the advent and proper utilization of high-resolution modalities of optical coherence tomography (OCT), it has now become possible to detect even the smallest and most deeply located ODD. This allows for ODD detection at a much earlier developmental stage than has previously been possible and enhances the possibilities of research in underlying mechanisms. A review of the literature on ODD was conducted using the PUBMED database. The review focuses on the current knowledge regarding pathogenesis, diagnostics, clinical disease-tracking methodologies, structure-function relationships and treatment strategies of ODD.

Prevalence and histopathological signatures of optic disc drusen based on microscopy of 1713 enucleated eyes

“…; Hamann et al. ). Optic disc drusen (ODD) are often suspected when discovering elevated optic discs in asymptomatic patients.…”

“…Discrepancies in reported prevalences between histopathological and clinical studies indicate difficulties in assessing ODD using conventional routine clinical examination techniques especially for deeper located ODD (Auw-Haedrich et al 2002;Johnson et al 2009;Hamann et al 2018). Optic disc drusen (ODD) are often suspected when discovering elevated optic discs in asymptomatic patients.…”

Patterns of macular inner retinal layers involvement in eyes with optic nerve head drusen

“…Ganglion cell loss and VF damage can occur in eyes with ONHD. [3,10] In this context, SD-OCT presents as an important tool not only for morphological analysis of optic disc topography in ONHD eyes (specially EDI-OCT, which allows better imaging of deeper structures) but it could be also useful for quantifying the anatomical damage to the peripapillary retina and macula. In this case series, investigating structural damage in eyes with ONHD by SD-OCT, we not only found pRNFL loss in the majority of these cases (68.4%) but also significant macular damage in almost half of these eyes (47.3%), despite relative mild-to-moderate functional damage (mean VFMD of −4.6 dB).…”

“…Even though several studies have reported on SD-OCT findings in eyes with ONHD, most of them focused on morphological analysis of the ONHD itself or pRNFL quantification. [7,9,10,13] There are scant data when it comes to a segmented macular evaluation in these patients. In this context, Pilat et al [11] found RNFL and inner plexiform layer thinning in the inner annulus of macular OCT analysis in eyes with ONHD when compared to healthy eyes.…”

“…[3,7] In contrast, when the lesions are located closer to the lamina cribrosa, they can be difficult to detect and may require imaging techniques for confirmatory diagnosis, including low gain B-scan ultrasonography, [3,8] autofluorescence, [9] and, more recently, optical coherence tomography (OCT). [3,10,11] An important feature of this condition is that ONHD may cause axonal damage through a compressive mechanism, leading to peripapillary retinal nerve fiber layer (pRNFL) thinning. [12,13] Clinically, this can be associated or not with detectable pRNFL defects (as accessible by retinography) and visual field (VF) loss (as accessible by automated perimetry).…”