Diagnosing Optic Disc Drusen in the Modern Imaging Era: A Practical Approach

Abstract

Optic disc drusen (ODD) are a well-recognised cause of an elevated optic disc appearance. When visible with ophthalmoscopy and fundus photography, ODD are readily identified. Yet, in more subtle cases of ODD, ancillary testing may be needed to render the diagnosis. Facilitating the diagnosis of ODD has clinical relevance, because affected individuals may otherwise undergo unnecessary costly and invasive investigations to rule out raised intracranial pressure and other causes of optic disc oedema. In this review, the role of established and emerging optical coherence tomography (OCT) techniques in the diagnosis and management of ODD cases is reviewed. A practical approach is taken to explain how to optimise use of commercially available OCT technology in the clinical setting. Optical coherence tomography provides many advantages over other imaging modalities in the diagnosis of ODD, including the ability to correlate retinal measures of neuroaxonal structure with drusen characteristics. Earlier spectral domain OCT techniques, however, were hindered by poor penetrance. In the modern imaging era, enhanced depth imaging OCT and swept source OCT enable higher resolution of ODD and other optic nerve head structures that might otherwise be mistaken for drusen. Ongoing studies featuring OCT angiography indicate that this technique may provide complementary information about microvascular supply that correlate with structural measures of optic nerve injury. Advances in OCT will continue to improve diagnostic accuracy and inform clinical understanding regarding structure-function correlations germane to the longitudinal follow up of ODD patients.

Understanding Pseudopapilledema on Spectral Domain Optical Coherence Tomography

“…5 Interestingly the HHL has also been reported to be the precursors of ONHD as they are also reportedly common in children. 22 They are often found in children with drusen and might represent early drusen in evolution. Lasse Malmquist et al have reported that super cial drusen were found in older age groups and median age for deep drusen was 21 years.…”

Branch retinal vein occlusion precipitated by compression between a major retinal artery and underlying optic disc drusen

“…We do recommend though, that OCT imaging of the deep structure of the optic disc-and not only the peripapillary nerve fibre layer-be included in routine OCT investigation. As the gold standard diagnostic for superficial and deep ODD, the international Optic Disc Drusen Studies Consortium recommends a dense 97-lines OCT covering the entire optic disc with enhanced depth imaging enabled and b-scan averaging of 30 or more (Costello et al 2020). ODD should be on the list of abnormalities that are looked for by OCT imaging and an appropriate scan protocol.…”

“…While large, superficial accumulations often protrude and lead to the characteristic changes that can be diagnosed by biomicroscopy, smaller and deeper located ODD are hard to detect (Costello et al. 2020).…”

“…Optic disc drusen (ODD) are acellular deposits located above the lamina cribrosa within the optic nerve head. While large, superficial accumulations often protrude and lead to the characteristic changes that can be diagnosed by biomicroscopy, smaller and deeper located ODD are hard to detect (Costello et al 2020).…”

Multimodal Imaging Features of Optic Disc Drusen

“…Although many hyper-reflective lines occur in isolation, sometimes they are associated with very small ODD that can be missed by OCT scans. 32,33 The optical properties that give rise to the hyper-reflective horizontal lines on OCT may also be a strong ''reflector'' on NIR. A few reports have described PHOMS in association with ODD on OCT B-scan.…”