REVIEW The usefulness of multimodal imaging for differentiating pseudopapilloedema and true swelling of the optic nerve head: a review and case series Clin Exp Optom 2015; 98: 12–24 DOI:10.1111/cxo.12177 Jaclyn Chiang *† MOptom PGCertOcTher Elizabeth Wong *† MOptom PGCertOcTher Andrew Whatham *† DPhil BOptom PGCertOcTher Michael Hennessy *§ MBiomedE FRANZCO Michael Kalloniatis *† PhD MScOptom PGCertOcTher Barbara Zangerl *† DVM PhD * Centre for Eye Health and † School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales, Australia § Ophthalmology, Prince of Wales Hospital, Randwick, Australia E-mail: bzangerl@cfeh.edu.au Ophthalmic practitioners have to make a critical differential diagnosis in cases of an elevated optic nerve head. They have to discriminate between pseudopapilloedema (benign eleva- tion of the optic nerve head) and true swelling of the optic nerve head. This decision has significant implications for appropriate patient management. Assessment of the optic disc prior to the advanced imaging techniques that are available today (particularly spectral domain optical coherence tomography and fundus autofluorescence), has mainly used diagnostic tools, such as funduscopy and retinal photography. As these traditional methods rely on the subjective assessment by the clinician, evaluation of the elevated optic nerve head to differentiate pseudopapilloedema from true swelling of the optic nerve head can be a challenge in clinical practice with patients typically referred for further neuroimaging investigation when the diagnosis is uncertain. The use of multimodal ocular imaging tools such as spectral domain optical coherence tomography, short wavelength fundus autofluorescence and ultrasonography, can potentially aid in the differentiation of pseudopapilloedema from true swelling of the optic nerve head, in conjunction with other clinical findings. By doing so, unnecessary patient costs and anxiety in the case of pseudopapilloedema can be reduced, and appropriate urgent referral and management in the case of true swelling of the optic nerve head can be initiated. Submitted: 12 February 2014 Revised: 27 March 2014 Accepted for publication: 1 April 2014 Key words: drusen of optic nerve head, multimodal imaging, optic nerve head, papilloedema, pseudopapilloedema Optic nerve head elevation results from a number of aetiologies which can be divided into two broad groups: pseudopapilloedema (benign elevation of the optic nerve head) and true swelling of the optic nerve head, such as occurs in papilloedema due to raised intracranial pressure. Figure 1 gives a clinical classification of optic nerve head elevation, 1 which is an overlapping feature between the two groups, and hence it is imperative that these conditions are accu- rately differentiated in clinical practice, as misdiagnosis has significant implications for patient management. The management of pseudopapilloedema encompasses routine review and urgent medical attention is not commonly required. In contrast, true swelling of the optic nerve head secondary to increased intracranial pressure, for example, demands accurate diagnosis and urgent management as it is potentially sight and life threatening. 2 Correct diagnosis of pseudopapilloedema is important to ensure appropriate management, avoid medical costs on unnecessary neurologic procedures and prevent any needless patient anxiety. 2 Conditions that give rise to pseudo- papilloedema include small crowded discs, tilted discs and optic nerve head drusen (Figure 1). Conditions that cause bilateral true swelling of the optic nerve head include those that are secondary to raised intracra- nial pressure (papilloedema). The vast majority of cases presenting with unilateral optic nerve head swelling and normal intrac- ranial pressure, such as inflammatory, ischaemic and infiltrative neuropathies, direct optic nerve compression, traumatic optic neuropathy, toxicity induced optic neuropathy and ocular hypotony, have systemic signs or symptoms which either precede ocular manifestation or have oph- thalmoscopic signs other than elevation of the optic disc pointing to its diagnosis. 3 A careful diagnostic work-up, including visual acuities, pupil responses, colour vision, ocular motility and visual fields, is imperative in the assessment of an elevated optic nerve head as characteristic changes in these clini- cal features, such as pain on eye movement, flame haemorrhages or cotton wool spots, can indicate optic nerve head pathology. It can be challenging to differentiate pseudopapilloedema from true swelling of the optic nerve head with standard clinical tests, such as slit lamp examination and fundus photography in the absence of other clinical signs and symptoms suggesting optic nerve head pathology. Where clinical results are uncertain, recently developed ocular imaging techniques such as spectral domain optical coherence tomography (OCT) and fundus autofluorescence, as well as the more established technique of B-scan ultra- sonography, are relatively non-invasive and have improved the ability to differentiate pseudopapilloedema from true swelling of the optic nerve head. The remainder of this article will give an overview of pseudopapilloedema and true swelling of the optic nerve head, followed by CLINICAL AND EXPERIMENTAL OPTOMETRY Clinical and Experimental Optometry 98.1 January 2015 © 2014 The Authors 12 Clinical and Experimental Optometry © 2014 Optometry Australia