UNASSIGNED: Around one in forty patients are diagnosed with optic disc drusen (ODD) during their lifetime. Complications of these acellular deposits range from asymptomatic visual field deficits to artery occlusion and subsequent cecity. Still, the pathogenesis of their emergence remains controversial. In particular, it was suggested 50 years ago that a narrow disc and scleral canal is one factor leading to axoplasmic flow disturbance, which induces ODD formation. However, this hypothesis is still debated today. To evaluate the basis of this theory, we will conduct a systematic review and meta-analysis of studies evaluating the scleral canal size in patients with ODD and in healthy subjects.
UNASSIGNED: We will search MEDLINE via PubMed, Cochrane, and EMBASE electronic databases to identify articles published before November 29, 2022 that measure the scleral canal size in patients with ODD and in healthy subjects. In addition, grey literature will be searched. The meta-analysis will include studies that include patients with a clinical or imaging diagnosis of ODD and healthy subjects. Additionally, we will perform a subgroup analysis to compare patients with buried ODD and patients with visible ODD. Extracted data from included studies will be presented descriptively, and effect sizes will be computed based on the recommendations from the Cochrane Collaboration handbook.
UNASSIGNED: The hypothesis that a narrow scleral canal is a risk factor of ODD has long been debated and this systematic review and meta-analysis should disentangle the different views. Understanding the underlying factors driving the development of ODD should help us focus on patients at risk and develop strategies to prevent advanced stages of the disease in these patients. Besides, focusing on patients with small scleral canals should help us derive associated factors and provide a better understanding of the pathology.
UNASSIGNED: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022375110.

Optic disc drusen (ODD) are calcium-containing deposits in the optic nerve head, capable of causing visual field defects and sudden visual loss. The underlying pathophysiology remains inadequately understood and treatment options are missing. In this paper, we systematically reviewed prevalence studies of ODD in non-selected populations to provide an overview of its prevalence, conducted meta-analyses to determine modality-specific prevalence estimates and performed a forecasting study to estimate current and future global population number of individuals with ODD. We searched 11 literature databases on 25 October 2022 for prevalence studies of ODD in non-selected populations. Eight eligible studies provided data from a total of 27 463 individuals. Prevalence estimates were stratified according to diagnostic modalities: ophthalmoscopy 0.37% (95% CI: 0.10-0.95%), fundus photography 0.12% (95% CI: 0.03-0.24%), spectral domain optical coherence tomography with enhanced depth imaging 2.21% (95% CI: 1.25-3.42%) and histopathology 1.82% (95% CI: 1.32-2.38%). Using histopathology-based summary prevalence estimate, we forecast 145 million individuals with ODD currently, a number expected to increase further due to world population growth. These numbers underscore the importance of including ODD in health education and highlight the necessity of continuing research in ODD.

Suspected optic disc swelling is a common presentation in children. The delineation between true optic disc swelling and pseudopapilloedema, its common masquerade, requires careful evaluation. A streamlined pathway is required to avoid unnecessary investigations.
Papilloedema requires urgent neuroimaging, however, perceived optic disc swelling is not always true papilloedema. This study aims to investigate the outcome of referrals for optic disc swelling and formulate features that may assist in investigation and diagnosis.
A retrospective review of referrals for optic disc swelling to the Queensland Children\'s Hospital, Australia, between January 2014 and June 2020 was undertaken.
Four hundred and ten children were referred for optic disc swelling. Sixty-six patients were confirmed with optic disc swelling, and 344 patients had pseudopapilloedema. The average age was 10.10 ± 3.57 and 9.90 ± 3.50 years, respectively. The most common aetiology of optic disc swelling was idiopathic intracranial hypertension (n = 25). Optic disc drusen constituted the majority of pseudopapilloedema (n = 239) and the remainder were crowded/tilted discs (n = 105). True optic disc swelling patients were more likely to experience headache (OR = 8.68, p < 0.01) and visual disturbance (OR = 2.14, p = 0.03). B-scan was the most sensitive for the detection of optic disc drusen (100%), followed by optical coherence tomography (70.38%) and fundus autofluorescence (44.86%). The retinal nerve fibre layer thickness was significantly thicker in true optic disc swelling compared to pseudopapilloedema (p < 0.01). Twenty-two (33.33%) true optic disc swelling patients and 33 (9.59%) pseudopapilloedema patients underwent neuroimaging prior to ophthalmology review.
Suspected optic disc swelling in children is most likely pseudopapilloedema. Referrals should include neurological assessment, visual acuity, fundus photography, and optical coherence tomography to assist in the triage for ophthalmic review. Neuroimaging prior to ophthalmic review should be discouraged for children without neurological symptoms.

Peripapillary hyperreflective ovoid mass-like structures (PHOMS) are a laterally bulging herniation of distended axons into the peripapillary region above the level of Bruch\'s membrane opening. Increased use of enhanced depth imaging-optical coherence tomography (EDI-OCT) in our evaluation of the optic nerve head (ONH) and greater recognition of the vast range of optic nerve pathologies with which PHOMS is associated provides convincing evidence that PHOMS is not just buried optic disc drusen (ODD) as previously described. The frequent coexistence of PHOMS with ODD, papilloedema, anterior ischaemic optic neuropathy, tilted optic disc syndrome, inflammatory demyelinating disorders and other diseases associated with axoplasmic stasis provides insight into its underlying pathophysiology. The present review will discuss the role of key imaging modalities in the differential diagnosis of PHOMS, explore the current literature on the relationship between PHOMS and common neuro-ophthalmic conditions, and highlight the gaps in our knowledge, with respect to disease classification and prognosis, to pave the way for future directions of research.

Increased intracranial pressure is the most common cause of papilledema. Multiple etiologies such as cerebral edema, hydrocephalus, space occupying lesions, infection, and idiopathic intracranial hypertension among others should be considered. Imaging plays a critical role in the detection of pathologies that can cause papilledema. MRI with contrast and CE-MRV, in particular, are key for the diagnosis of idiopathic intracranial hypertension. This review will focus in common and infrequent causes of papilledema, the role of imaging in patients with papilledema as well as its potential mimickers.

BACKGROUND: Optic disc drusen (ODD) are acellular deposits in the prelaminar optic nerve head. The most accredited theory is that they are secondary to abnormalities in axonal metabolism and degeneration, but the pathogenesis is not clear to date.
UNASSIGNED: Although ODD are often considered a benign condition, the great majority of patients with ODD show visual field defects and are at higher risk for developing anterior ischemic optic neuropathy. ODD are classified as superficial or buried, with the latter being often misdiagnosed as papilledema with optic nerve head swelling, leading to an unnecessary investigation for causes of increased intracranial pressure.
OBJECTIVE: The recent technological improvements in OCT imaging which allowed an earlier and more certain diagnosis even of the smallest ODD, renovated the interest around this pathology. However, an updated systematic review is still missing. Therefore, the aim of this work is to provide a concise yet comprehensive overview of the current state of art, focusing on pathophysiology, clinical presentation, diagnostic methods, treatment modalities and potential future perspectives of this condition.